The verdict in three sentences
Above 500 temps a month, a London agency still running contracts and timesheets on spreadsheets loses money on every assignment, through payroll errors and admin time. Custom staffing software priced at GBP 45,000 to 110,000 automates contracts, mobile timesheets, payroll, HMRC RTI submissions and IR35 status determinations. Payback typically lands between 10 and 18 months.
Where time and money go in a 900-temp agency
Every assignment creates a client terms document, a worker assignment contract, weekly timesheets, a payroll run, a client invoice and RTI data. Multiplied by 900, these flows swamp a team. For contractors working through their own limited company, the agency or client must also issue and track a Status Determination Statement under the off-payroll rules.
| Monthly task | Manual process | With dedicated software |
|---|---|---|
| Issuing 1,800 documents (assignment + client terms) | 15 to 20 min each, 450 to 600 h | 2 to 3 min, 60 to 90 h |
| Timesheet collection | Paper or WhatsApp, 3 to 5 days of chasing | Geolocated mobile clock-in, real time |
| Payroll errors | 4 to 8% of payslips | Under 1% |
| HMRC RTI submissions | Re-keying, 2 to 3 days | File generated automatically |
| IR35 Status Determination Statements | Word templates, poor audit trail | Workflow with reasons and dated record |
| Client invoicing | 5 to 10 day lag | Invoice issued on timesheet approval |
| Full-time admin equivalent | 4 to 5 people | 1.5 to 2 people |
The invoicing lag matters as much as lost time: on GBP 1.2 million of monthly billings, invoicing 7 days earlier frees roughly GBP 280,000 of working capital.
2026 budget: SaaS, payroll bureau or custom build
UK staffing SaaS platforms are mature but charge per active worker, and connecting them to your own client portal or niche rules often means extra fees. Custom makes sense when volume is high or workflows are specific.
| Option | Upfront cost (GBP) | Recurring cost | Fit with your processes |
|---|---|---|---|
| UK staffing SaaS | 5,000 to 15,000 setup | GBP 4 to 10 per active worker per month | Good, but standard |
| Payroll bureau + spreadsheets | 3,000 to 8,000 | GBP 3 to 6 per payslip | Compliant payroll, rest manual |
| Custom core (contracts, payroll export, RTI) | 45,000 to 70,000 | GBP 8,000 to 14,000 per year | Full |
| Full custom (+ timesheets app, client portal, BI) | 75,000 to 110,000 | GBP 12,000 to 20,000 per year | Full |
| E-signature on contracts | Integration included | GBP 0.40 to 1.20 per envelope | Legally valid in England and Wales |
| Mobile timesheet app | 12,000 to 25,000 | Hosting included | Geolocation and photo |
With 1,800 e-signed documents a month at GBP 0.80, e-signature costs about GBP 1,440 a month, easily offset by removing printing, couriers and unreturned contracts.
Mini case study
Priya runs a London agency specialising in logistics and warehousing, placing 900 temps a month. Her admin team of 5 costs GBP 3,200 each per month fully loaded, GBP 16,000 a month. Payroll errors (6% of payslips) generate around GBP 6,000 a month in corrections and lost hours.
She invests GBP 90,000 in custom software with mobile timesheets, plus GBP 16,000 a year for maintenance and GBP 17,000 a year for e-signature. Estimated result: 2 roles moved to sales (GBP 6,400 a month) and errors down to 1% (GBP 5,000 saved a month). Gain: GBP 11,400 a month, GBP 136,800 a year, minus GBP 33,000 of recurring costs: GBP 103,800 net per year. Payback: about 10 months, shorter once faster invoicing is factored in.
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FAQ
How much does custom staffing agency software cost in London in 2026?
Between GBP 45,000 and 110,000 depending on scope, plus GBP 8,000 to 20,000 a year for maintenance and hosting. A core of contracts, payroll export and RTI sits around GBP 55,000.
Can the software handle IR35 off-payroll rules?
Yes: it can run a status questionnaire, issue the Status Determination Statement with reasons and keep a dated record. That audit trail is what HMRC looks for in a review.
Is e-signature valid for temp worker contracts in the UK?
Yes, electronic signatures are accepted for employment and assignment contracts in England and Wales. Cost ranges from GBP 0.40 to 1.20 per envelope depending on provider and volume.
How do mobile timesheets work?
The temp clocks in from a phone with geolocation and optional photo, and the client supervisor approves hours in a portal. Timesheets are available in real time instead of after 3 to 5 days of chasing.
What implementation timeline should we plan?
Allow 4 to 6 months, including 3 weeks of scoping and 3 to 4 weeks of parallel running with the old system on one or two branches before full roll-out.
Let's scope your project. Tell us your temp volume, client sectors and current tools, and we will price custom staffing software between GBP 45,000 and 110,000, delivered in 4 to 6 months. 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.
