People ops for UK scale-ups
Reviewed by Mellow Editorial Team, HR & payroll content team
Running people operations well at a scale-up means building HR infrastructure that keeps pace with headcount growth without adding unnecessary complexity. The priority is getting the legal foundations right first, then building consistent processes around them.
Get the employment basics right before you scale
Every hire adds legal obligation. From day one of employment, workers are entitled to a written statement of particulars — effectively a contract — and the Employment Rights Act 2025 has strengthened day-one rights further, including around unfair dismissal protections. Getting these documents right at the start is far cheaper than correcting them later.
Check each role is classified correctly. Employees, workers and genuine self-employed contractors have different rights and different tax treatment. HMRC's CEST tool can help you assess IR35 status for contractors, but you remain responsible for getting it right. Misclassification — particularly treating workers as contractors to avoid employer National Insurance at 13.8% — is one of the most common and costly mistakes fast-growing companies make.
Build a payroll process that scales with you
When you have five people, payroll is manageable in a spreadsheet. At thirty, it becomes a liability if you have not formalised it.
The core requirement is Real Time Information reporting. You must submit a Full Payment Submission to HMRC on or before each payday, every time. Late submissions attract penalties, and they compound quickly if you are running a monthly payroll for a growing team.
Key annual obligations to diary in:
- P60s to all employees by 31 May after each tax year ends
- P11Ds (or payrolling of benefits) submitted to HMRC by 6 July for any taxable benefits in kind
Auto-enrolment is non-negotiable. Once employees meet the age and earnings criteria, you must enrol them in a qualifying pension scheme, contribute at least 3% of qualifying earnings as the employer, and ensure employees contribute a minimum of 5%. Missing re-enrolment deadlines — which recur every three years — is a frequent compliance gap at companies that grew quickly and then forgot to check.
As headcount grows, consider whether your payroll is being run in-house, through an accountant or via a dedicated payroll provider. Each model works, but ownership and accountability need to be clear. For companies with employees in multiple countries, how Mellow runs payroll across six countries on one platform is worth reading before you build a patchwork of local solutions.
Design your leave and absence framework early
Statutory annual leave is 5.6 weeks — 28 days including bank holidays for a full-time five-day-week employee. Many scale-ups offer more than this, which is fine, but you need a written policy that covers how leave is booked, whether untaken leave carries over, and how it is paid out on termination.
Sick leave, family leave and other statutory entitlements require documented processes. Statutory Sick Pay and statutory family-leave pay have qualifying conditions, rates and notification requirements that you need to handle consistently. Inconsistency across teams creates both legal risk and genuine employee relations problems.
A lightweight HR system — even a basic one — pays for itself quickly when you are managing leave across twenty or more people. Tracking it in a shared spreadsheet does not scale and leads to disputes.
Build a performance and development structure before you need it
Scale-ups often focus entirely on hiring and ignore what comes after. By the time you have fifty people, the absence of a performance framework becomes visible: managers are giving inconsistent feedback, decisions about pay progression are ad hoc, and you have no defensible basis for any capability or conduct process.
You do not need an elaborate system. You need:
- A regular review cycle, even if it is lightweight
- Written role expectations so employees know what good looks like
- A documented process for managing underperformance before it reaches a formal stage
Getting these in place at twenty people rather than eighty is significantly easier. It also means that when you do need to use a formal process — whether that is a performance improvement plan or a disciplinary — you are working within an established framework rather than improvising under pressure.
Think about people ops as infrastructure, not overhead
The companies that struggle most at scale are the ones that treated HR as purely administrative until something went wrong. Tribunal claims, failed hires, high attrition and poor manager effectiveness all have operational and financial costs that dwarf the cost of building decent people processes earlier.
The practical starting point is an audit of what you have: contracts, payroll compliance, pension enrolment, leave records and any documented policies. Most scale-ups find gaps. Addressing them systematically — rather than reactively — is what separates the companies that scale cleanly from the ones that hit painful friction at a hundred people.
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