The verdict in three sentences
For an agency placing 1,400 temporary workers a month in London, custom back-office software costs, as a 2026 order of magnitude, £100,000 to £220,000 depending on modules and integrations. The return shows up in timesheet handling time, payroll and invoicing errors and the reliability of AWR compliance, where a single equal-treatment claim can cost more than a module. If your team still rekeys hours from paper timesheets or emailed spreadsheets, the project typically pays back in 9 to 18 months.
What the software must cover, module by module
A UK employment business operates under a tight framework: the Conduct of Employment Agencies and Employment Businesses Regulations 2003, a Key Information Document for every new worker, right-to-work checks, PAYE Real Time Information, pension auto-enrolment and the Agency Workers Regulations 2010, which grant equal pay and conditions after 12 weeks in the same role. The software has to encode those rules, not just store CVs.
| Module | Key function | Indicative 2026 cost (GBP, ex VAT) | Build time |
|---|---|---|---|
| Worker records | Right-to-work evidence, qualifications, availability, KID issued | 10,000 to 22,000 | 4 to 6 weeks |
| Assignments | Auto-generated assignment terms, extensions, e-signature | 12,000 to 25,000 | 4 to 6 weeks |
| Mobile timesheets | Worker entry, client sign-off, offline mode | 15,000 to 35,000 | 6 to 8 weeks |
| Temp payroll | Overtime, rolled-up holiday pay at 12.07%, pension, RTI files | 20,000 to 45,000 | 8 to 10 weeks |
| Client invoicing | Charge rates per assignment, invoices from approved timesheets, chasing | 10,000 to 22,000 | 4 to 6 weeks |
| AWR compliance | 12-week qualifying clock, comparator pay, breaks in assignment | 12,000 to 28,000 | 4 to 6 weeks |
| Management dashboard | Gross margin per client, fill rate, time to fill | 8,000 to 18,000 | 3 to 4 weeks |
The modules add up to £87,000 to £195,000, plus project management, data migration and consultant training. Budget annual running costs (hosting, corrective and evolutive maintenance) of around 12 to 18% of the initial build.
The most underestimated module is AWR tracking. Workers move between clients, take breaks that may or may not reset the 12-week clock, and the comparator pay must be captured from the hirer. Getting it wrong exposes the agency to Employment Tribunal claims and damages the client relationship.
Where the return on investment hides
The gains concentrate on repetitive tasks that can be costed precisely. The table assumes 1,400 workers a month, 900 assignments created or extended and monthly turnover of £2,400,000.
| Item | Manual process | With the software | Estimated monthly gain |
|---|---|---|---|
| Timesheet entry | 6 min each, 140 h | 1 min each, 23 h | 117 h freed |
| Assignment paperwork | 20 min each, 300 h | 3 min each, 45 h | 255 h freed |
| Payroll errors | 2.5% of payslips | 0.5% of payslips | 28 corrections avoided |
| Invoicing leakage | 1.2% of billed turnover | 0.3% of billed turnover | up to £21,600 |
| Invoice issue delay | 7 days after week end | next day | 6 days of cash gained |
| AWR exposure | manual spreadsheet tracking | automatic alerts at week 10 | claims avoided |
The six days gained on invoicing release roughly £480,000 of working capital once, at this turnover. For many boards that is the decisive argument, more than the hours saved.
Off-the-shelf platform or custom build
UK staffing platforms exist and work well for standard agencies, at roughly £3 to £8 per active worker per month. At 1,400 workers that is £250,000 to £670,000 over five years, with limited control over workflows and integrations. Custom software makes sense when your margin depends on a specific process: complex shift patterns, multi-site clients, umbrella company checks or a proprietary pricing model. Below 300 workers a month, a standard platform plus a few automations is usually enough.
Mini case study
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Daniel runs a staffing agency in Croydon placing 1,400 workers a month in logistics and facilities. He scopes a £160,000 build with £36,000 a year in running costs, or £3,000 a month. His monthly gains: 372 hours freed at £22 per loaded hour, £8,184; 28 payroll corrections avoided at £45 each, £1,260; and, to stay prudent, only half the invoicing leakage recovered, £10,800. Total: £20,244 a month, minus £3,000 running costs, £17,244 net. The build is covered in 160,000 / 17,244 = about 9 months, before counting the working capital released.
FAQ
How long does deployment take?
Plan 5 to 8 months for the full scope, delivered in phases. A first release covering assignments and timesheets can go live in 10 to 12 weeks and starts generating savings before payroll is migrated.
Can the software submit RTI and pension data?
It generates Full Payment Submissions and pension contribution files in the expected formats, with pre-submission checks. Your payroll lead keeps final sign-off, which typically removes 2 to 3 late or corrected submissions a year.
What about workers without a recent smartphone?
A lightweight web app under 2 MB works offline and syncs when the network returns. For the 5 to 10% of workers without a smartphone, the client supervisor enters and approves hours for the team.
How is worker data protected under UK GDPR?
Identity documents are encrypted, access is logged and inactive records are purged on a defined schedule, for example 6 years after the last assignment. Hosting in a UK or EU data centre simplifies your ICO documentation.
Can we start with a smaller budget?
A first scope of worker records, assignments and timesheets sits around £45,000 to £65,000. Payroll, invoicing and AWR tracking are added afterwards on the same database.
Let's scope your project. Send us your monthly worker volume, current tools and priorities, and we will price a phased scope with an indicative budget and go-live calendar. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
