Form N252 UK: Notice of Commencement of Assessment Explained

At a glance

• What it does: Form N252 (notice of commencement of assessment of bill of costs) starts detailed assessment proceedings under CPR Part 47.
• Deadline to serve it: within 3 months of the judgment, order or other event that gave the right to costs (CPR 47.7).
• Deadline to respond: the paying party has 21 days from service of the N252 to serve points of dispute (CPR 47.9(2)).
• If nothing is served in time: the receiving party can request a default costs certificate using Form N254 for the full amount claimed (CPR 47.9(4), 47.11).
• Points of reply: the receiving party has 21 days to reply to any points of dispute served (CPR 47.13).
• Provisional assessment: bills of £75,000 or less (excluding VAT) are normally assessed on the papers rather than at a hearing, and the court will award no more than £1,500 for the costs of that provisional assessment itself (CPR 47.15, PD47 para 14.1).
• Hearing deadline: where points of dispute are served, the receiving party must request a detailed assessment hearing within 3 months of the CPR 47.7 deadline expiring — in practice, around 6 months from the original order in total (CPR 47.14).

What Form N252 is and when it's used

After a judgment, order or settlement establishes that one party must pay another party's legal costs, the party who is owed the money (the receiving party) does not simply send an invoice. Instead, if the costs cannot be agreed, they must go through detailed assessment — a formal court process for scrutinising a bill of costs, item by item, under CPR Part 47.

Form N252 is the document that opens that process. Served together with an itemised bill of costs, it tells the paying party: here is what we are claiming, here is the basis for it, and here is when your time to respond starts running. Practice Direction 47 requires the notice of commencement to show, as separate items, the total costs claimed in the bill and the extra sum that would become payable by way of fixed costs and court fees if a default costs certificate is obtained instead.

Serving the N252 is not a ruling on whether the costs claimed are reasonable. That question is decided later — either by agreement between the parties, through provisional assessment on the papers, or at a detailed assessment hearing before a costs judge or district judge.

The legal basis: CPR Part 47

Detailed assessment proceedings, and the N252's role in starting them, are governed by CPR Part 47. The key rules are:

• CPR 47.6 — commencement of detailed assessment proceedings: the receiving party serves the N252 and the bill of costs (and, where required, a phase-by-phase costs breakdown) on the paying party and any other relevant party.
• CPR 47.7 — the period for commencing detailed assessment proceedings: 3 months, running from different trigger events depending on how the right to costs arose.
• CPR 47.8 — sanctions where the receiving party is late commencing proceedings.
• CPR 47.9 — points of dispute: the 21-day window to respond, and the consequence of not serving them.
• CPR 47.11 and 47.12 — default costs certificates, and setting them aside.
• CPR 47.13 to 47.15 — the optional reply, the detailed assessment hearing, and provisional assessment for smaller bills.
• CPR 47.16 and 47.17 — interim and final costs certificates.
• CPR 47.20 — who pays the costs of the detailed assessment proceedings themselves.

The full timeline, stage by stage

| Stage | Governing rule | What happens | Time limit | |---|---|---|---| | Commencement | CPR 47.6 | Receiving party serves the N252, the bill of costs, and (if required) a phase-by-phase breakdown | Within 3 months of the costs order (CPR 47.7) | | Points of dispute | CPR 47.9 | Paying party challenges individual items in the bill | 21 days from service of the N252 | | Default costs certificate | CPR 47.9(4), 47.11 | Receiving party requests payment in full if no points of dispute arrive in time | Form N254; any time after the 21-day window closes | | Points of reply (optional) | CPR 47.13 | Receiving party responds to the points of dispute | 21 days from service of the points of dispute | | Detailed assessment hearing request | CPR 47.14 | Receiving party files a request for the bill to be assessed | Form N258; within 3 months of the CPR 47.7 deadline expiring | | Provisional assessment | CPR 47.15 | Bills of £75,000 or less (excluding VAT) assessed on the papers instead of at a hearing | Applies automatically to eligible bills unless the court directs otherwise | | Final costs certificate | CPR 47.17 | Receiving party files a completed bill showing the amount finally due | Within 14 days of the hearing, or the provisional assessment, ending |

Step 1: the receiving party must serve the N252 within 3 months

CPR 47.7 sets out a table of trigger events and deadlines. The most common is straightforward: where the right to detailed assessment arises from a judgment, direction, order, award or other determination, the receiving party has 3 months from the date of that judgment or order to serve the N252 and bill of costs. If detailed assessment was stayed pending an appeal, the 3 months runs instead from the date of the order lifting the stay.

Two other triggers apply less often: where a claim is discontinued under Part 38, the 3 months runs from service of the notice of discontinuance (or from dismissal of an application to set that notice aside); where a party accepts a Part 36 offer to settle, it runs from the date the right to costs arose.

If the receiving party misses the 3-month deadline, the paying party does not have to simply wait it out. Under CPR 47.8, they can apply for an order requiring the receiving party to commence proceedings within a time set by the court — and the court can direct that some or all of the costs will be disallowed if that new deadline is also missed. Even without an application, a receiving party who commences proceedings late risks losing interest that would otherwise have run on the costs.

Step 2: the paying party has 21 days to serve points of dispute

Once served with the N252, the paying party — and any other party to the detailed assessment proceedings — has 21 days from the date of service to dispute any item in the bill by serving points of dispute, under CPR 47.9(2). Points of dispute should be served on the receiving party and on every other party to the proceedings.

This deadline matters more than it might first appear. Under CPR 47.9(3), a party who serves points of dispute after the 21 days has expired generally cannot be heard further in the proceedings unless the court gives permission. In practical terms, that can mean losing the ability to challenge the bill at all.

If you do nothing: the default costs certificate

If the 21-day period for serving points of dispute expires without any being served, CPR 47.9(4) allows the receiving party to file a request for a default costs certificate. That request is made using Form N254; the certificate itself is issued as Form N255 (County Court) or N255(HC) (High Court). Under CPR 47.11, a default costs certificate includes an order to pay the costs to which it relates — in effect, the full sum claimed, without the paying party having had any say over individual items. Practice Direction 47 fixes the costs added for obtaining the certificate at £80 plus any appropriate court fee, unless the court orders otherwise — a figure worth checking against the current Practice Direction before relying on it, as fixed sums of this kind are periodically reviewed.

Once a default costs certificate has been issued, if any party serves points of dispute before it was issued, CPR 47.9(5) says the court cannot go on to issue the certificate — so points of dispute served even at the last moment, but before the certificate is actually issued, can still be effective.

Setting aside a default costs certificate

A default costs certificate is not always the end of the story. Under CPR 47.12, the court will set aside a default costs certificate if the receiving party was not actually entitled to it — for example, if the N252 was not properly served. In other cases, the court has discretion to set aside or vary the certificate if it appears there is some good reason for the detailed assessment proceedings to continue. This is not automatic, and the paying party will usually need to apply to the court promptly and explain the delay — Practice Direction 47 specifically directs the court to consider whether the application was made promptly.

Step 3: points of reply and negotiating a settlement

Serving points of dispute does not have to lead straight to a hearing. Under CPR 47.13, once points of dispute have been served, the receiving party may serve a reply — commonly called points of reply — within 21 days of being served with the points of dispute. Practice Direction 47 requires any reply to be limited to points of principle and concessions only, without general or specific denials or standard-form responses. This exchange often narrows the areas of disagreement considerably, and many costs disputes settle at this stage without ever reaching a hearing.

Written offers to settle the costs of the underlying proceedings, made without prejudice save as to the costs of the detailed assessment proceedings, can also influence who ultimately pays for the assessment process itself — CPR 47.20(4) applies modified Part 36 principles to offers made in this context.

Step 4: requesting a detailed assessment hearing — or provisional assessment

Where points of dispute have been served and the dispute has not settled, CPR 47.14 requires the receiving party to file a request for a detailed assessment hearing within 3 months of the expiry of the CPR 47.7 period for commencing proceedings. Combined with the initial 3-month deadline to serve the N252, this means the request for a hearing generally needs to be made within around 6 months of the original costs order. As with the earlier deadlines, missing it exposes the receiving party to a court order compelling them to act, and the possible loss of costs or interest.

Provisional assessment for bills of £75,000 or less

Not every detailed assessment reaches an oral hearing. Under CPR 47.15, where the costs claimed are £75,000 or less (excluding VAT) — a threshold set by paragraph 14.1 of Practice Direction 47 — the court will normally carry out a "provisional assessment" on the papers, based on the bill, the supporting documents, and the points of dispute and any reply, requested using Form N258. No party attends: the assessment is done entirely on the papers, and Practice Direction 47 asks the court to use its best endeavours to complete it within 6 weeks of receiving the request.

The maximum the court will award any party for the costs of a provisional assessment that goes no further is £1,500 plus VAT and any court fees paid, excluding the separate cost of drafting the bill itself (CPR 47.15(5)). If either party wants to challenge the outcome, they must, within 21 days of receiving the provisionally assessed bill, file and serve a written request for an oral hearing on the specific items they want reviewed. The party requesting that hearing will usually have to pay its costs unless they achieve an adjustment of 20% or more of the sum provisionally assessed, or the court orders otherwise.

Worked example: a straightforward costs assessment timeline

The dates below are illustrative, not a real case, but show how the deadlines interact in practice.

A County Court judgment on 15 January orders the defendant to pay the claimant's costs, to be assessed if not agreed. The claimant's solicitors are the receiving party; the defendant is the paying party.

1. 15 January — the costs order is made. The CPR 47.7 clock starts running.
2. By 15 April (3 months later) — the receiving party must serve the N252 and bill of costs, or risk sanctions under CPR 47.8. They serve it on 2 April, comfortably inside the deadline.
3. By 23 April (21 days after service) — the paying party's deadline to serve points of dispute under CPR 47.9(2). The bill totals £42,000, which is below the £75,000 provisional assessment threshold in CPR 47.15. The paying party serves points of dispute on 20 April, disputing the hourly rate claimed for one fee-earner and two disbursements.
4. By 11 May (21 days after the points of dispute) — the receiving party may, but does not have to, serve points of reply under CPR 47.13. They serve a short reply conceding one disbursement and maintaining the hourly rate.
5. By 15 July (3 months after the CPR 47.7 deadline of 15 April expired) — the receiving party must file a request for assessment on Form N258 under CPR 47.14. Because the bill is under £75,000, this triggers provisional assessment under CPR 47.15 rather than a hearing.
6. The court provisionally assesses the bill on the papers. Either side then has 21 days from receiving the provisionally assessed bill to request an oral hearing on specific items — but doing so risks having to pay for that hearing unless the adjustment achieved is 20% or more of the provisionally assessed sum.

Now compare a variation: if the paying party in this example had served no points of dispute at all by 23 April, the receiving party could, from 24 April onwards, request a default costs certificate on Form N254 for the full £42,000 under CPR 47.9(4) and 47.11 — without the provisional assessment stage ever being reached.

Interim and final costs certificates

The court is not limited to waiting until the very end of the process to certify what is owed. Under CPR 47.16, once the receiving party has filed a request for a detailed assessment hearing, the court may issue an interim costs certificate for whatever sum it considers appropriate — useful where part of the bill is not seriously in dispute.

Once a hearing (or provisional assessment) is complete, CPR 47.17 requires the receiving party to file a "completed bill" — showing the amount due following assessment — within 14 days of the end of the hearing. The court then issues a final costs certificate — Form N256(CC) in the County Court, or N256(HC) in the High Court — which is served on the parties and includes an order to pay the costs assessed.

Who pays for the detailed assessment itself

Going through detailed assessment has its own costs, separate from the underlying bill. Under CPR 47.20, the receiving party is generally entitled to recover the costs of the detailed assessment proceedings themselves, unless a rule, practice direction or court order says otherwise. When deciding whether to depart from that default position, the court takes into account the conduct of all the parties, how much the bill of costs was reduced during the process, and whether it was reasonable for a party to claim — or to dispute — a particular item.

Court fees for detailed assessment proceedings

There are court fees at more than one stage of this process — for example, requesting a detailed assessment hearing using Form N258 attracts a fee that scales with the size of the bill being assessed, and other applications within the proceedings may carry their own fees. These fees are set out in the civil and family court fees schedule (EX50) and are reviewed periodically, so always check GOV.UK for the current fee before submitting a form or making a payment.

What to do if you've just received an N252, or need to serve one

1. Check the claim details carefully. Confirm the case number, the parties' names, and the court, against the original costs order — any mismatch is worth querying before you take any further step.
2. Read the bill of costs line by line. The N252 should arrive with a detailed bill showing each item of work, hourly rates, disbursements and VAT. Decide which items look reasonable and which you might want to challenge.
3. Diarise the 21-day deadline immediately. From the date the N252 is served, the paying party has 21 days to serve points of dispute — missing it risks losing the right to challenge the bill and facing a default costs certificate for the full amount.
4. If you're the receiving party, diarise your own deadlines. The N252 itself must be served within 3 months of the costs order, and — if points of dispute are served — a request for a detailed assessment hearing generally needs to follow within a further 3 months.
5. Draft specific, item-by-item points of dispute if you want to challenge the bill. Generic objections carry little weight; identify the item, explain why it's disputed, and suggest an alternative figure where you can.
6. Consider negotiation before a hearing. Points of reply, and direct negotiation between the parties, resolve most costs disputes without the time and expense of a hearing or provisional assessment challenge.
7. Take advice early if the sums involved are significant, or if you are unsure whether provisional assessment or a full hearing applies to your bill.

If you are dealing with other County Court paperwork alongside an N252, our practical guide to County Court forms and plain-English glossary of County Court terminology cover the surrounding process — including terms like "receiving party" and "paying party" used throughout this guide.

This guide provides general information about Form N252 and detailed assessment of costs in England and Wales. It is not legal advice and is not a substitute for advice tailored to your specific circumstances. The law described was accurate as at July 2026 and is subject to change — always check GOV.UK and legislation.gov.uk for the most current position.

Last reviewed: July 2026 by a non-practising solicitor · Next review due: July 2027 or on legislative change.