Service Level Agreements UK: Drafting Guide 2026

What this document is

An SLA is a written commitment to specific standards of performance. It sits either as a schedule to a main services contract or as a standalone document that the contract refers to. The main contract sets out the commercial terms: price, duration, payment, termination, liability.

The SLA handles the operational detail: what counts as acceptable performance, how that performance is measured, what happens when something slips, and how both sides raise and resolve issues. What separates an SLA from a general statement of services is that its standards are supposed to be testable.

Instead of promising 'prompt support', an SLA commits to a response time measured in hours or minutes. Instead of 'reliable uptime', it specifies a percentage measured over a defined period. That specificity is what makes the document useful to both sides.

The supplier knows exactly what they have to hit. The customer knows exactly what they are paying for, and has a clear basis for raising a problem when performance falls short.

How to use this document

1. Define the services with precision. Start by describing, in plain language, what the supplier is actually delivering. Avoid vague phrases like 'support services' or 'ongoing maintenance'. Break the service into its components, such as helpdesk cover, incident response, scheduled maintenance, reporting, and say who is responsible for each part. This is the foundation everything else rests on.
2. Set measurable performance standards. For each service, pick metrics that can be objectively recorded. Typical examples include availability percentages, response times by priority level, resolution times, first-contact fix rates, and scheduled maintenance windows. Keep the number of metrics manageable. Ten well-chosen measures are more useful than thirty that nobody tracks.
3. Agree how performance is monitored and reported. Decide who measures what, how often reports are produced, and what the reports must contain. Most SLAs include monthly performance reports with year-to-date figures. Agree in advance how disputed measurements are resolved, because this is where many SLA relationships come unstuck.
4. Build in consequences for missed targets. Without consequences, an SLA is just a wish list. Common remedies include service credits, escalation to senior management, rectification plans, and termination rights for persistent or material breach. Service credits are the most common approach in UK commercial contracts, and they need to be calibrated so they matter without being punitive.
5. Schedule regular reviews. Business needs change, and an SLA written at day one may not fit eighteen months in. Set a formal review cycle, typically annual or six-monthly, where both sides look at whether the metrics still reflect what matters, whether the service mix has shifted, and whether the commercial terms still align with the performance expectations.

Common questions