How London payroll bureaus and in-house software compare on cost and compliance

What to take away

• Payroll software suits London employers with steady headcount, clean data and someone senior enough to own RTI submissions.
• A London payroll bureau suits multi-entity, high-turnover or internationally mobile workforces, at a fee per payslip or per month.
• The cost gap is rarely the licence fee. It is the salary, pension admin and correction time behind in-house processing.
• Compliance duties do not transfer when you outsource. Under UK GDPR the employer stays the controller, the bureau acts as processor.
• Benchmark pay against ONS earnings data and plan uplifts against ONS inflation figures before signing either contract.

What a London payroll bureau actually does for an employer

A bureau takes your employee data, runs the calculations and files to HMRC under Real Time Information. The employer still holds the legal duty to report accurately and on time. The bureau is the agent doing the keystrokes.

Day to day that covers gross to net calculations, PAYE and National Insurance deductions, statutory payments, pension deductions and the Full Payment Submission. Most London bureaus also handle P45s, P60s and starter declarations.

Outsourcing usually adds year-end processing, P11D support and liaison with HMRC when a query lands. Some bureaus run auto-enrolment assessments and upload contributions to The Pensions Regulator-compliant schemes.

In London the work skews complex. Multi-entity groups, share schemes, foreign nationals and monthly bonus cycles are routine. A bureau that only handles single-company, salaried payrolls will struggle with a Mayfair holding company running six payrolls.

Pricing models vary. Some charge per payslip, some per month per client, some a retainer plus transaction fees. The pricing models used across England reward you for stable headcount and penalise constant churn.

A bureau also absorbs the software licence, the BACS submission and the HMRC recognition checks. That is the appeal: one invoice instead of a stack of them.

Running payroll in-house with software: the real cost lines

In-house payroll software is a licence or subscription plus your own labour. The licence looks cheap next to a bureau quote. The labour is where the money goes.

Budget for these lines.

1. Software subscription, usually banded by employee count.
2. A named payroll administrator, part time or full time.
3. Cover for holidays and sickness, because payroll cannot wait.
4. Pension administration and contribution uploads.
5. Year-end and P11D work, often the crunch point.
6. Training on RTI changes and National Minimum Wage uplifts.

A part-time payroll administrator in London costs materially more than the same role outside the capital. Salary expectations follow local market rates, and ONS earnings and working hours data is the sensible benchmark when you build the case.

Software alone does not process payroll. Someone reconciles the gross to net report, checks the variance against last month and approves the BACS file. If that person is your finance director, you have not saved the salary, you have moved it.

The licence fee is also not the whole software cost. Parallel runs during migration, additional company codes, and payslip portal add-ons are the costs employers miss when they compare a quote against a bureau fee.

Compliance differences between outsourcing and in-house

Compliance duty sits with the employer either way. GOV.UK's guidance on running payroll sets out the reporting, deduction and payment obligations that apply whether you process internally or pay an agent.

RTI is the core. You must send an FPS on or before each payday, and an Employer Payment Summary when a period has no payments. Late or wrong submissions attract HMRC penalties. A bureau reduces the risk of missing a deadline. It does not remove your liability.

Auto-enrolment adds a second regulator. The Pensions Regulator expects you to assess workers, enrol eligible staff and pay contributions on time. Bureaus often run the assessment and the upload. The declaration of compliance remains the employer's.

Data protection splits the roles. Under UK GDPR the employer is the controller and the bureau is the processor, as the ICO explains in its guidance on controllers and processors. That means a written processor contract, defined instructions and breach notification terms.

In-house processing keeps payroll data inside your own systems, which some employers prefer for confidentiality. It also puts the breach risk, the access controls and the retention schedule squarely on your own IT and HR teams.

National Minimum Wage and National Living Wage rates change each April. Someone has to update the software, check the affected staff and evidence the review. That task exists in both models.

Named providers and how their London offers compare

London has the deepest pool of bureaus and payroll software vendors in the UK. The table below compares typical offers, not quotations. Fees move with headcount and complexity.

Provider	Model	Typical London fit	Compliance handling
Payroll software	In-house licence or subscription	Employers with steady headcount and internal admin	You file RTI, you run auto-enrolment
BrightPay	In-house software	Small London firms wanting low licence cost	You file RTI, bureau add-on available
Sage	Software and bureau services	Mid-sized firms already on Sage accounting	RTI filing, pension modules
Xero Payroll	Software add-on	Small employers on Xero books	RTI filing, limited complexity
Moorepay	Bureau and managed payroll	Multi-entity London groups	RTI, auto-enrolment, year-end
MHR	Software and managed service	Larger employers with complex pay	RTI, pensions, analytics
Azets	Bureau and outsourced payroll	Groups wanting full outsourcing	RTI, pensions, P11D
LivePay	Bureau	SMEs wanting a low-touch service	RTI, auto-enrolment

Software vendors sell you the tool. Bureaus sell you the outcome. Moorepay, MHR, Azets and LivePay sit on the bureau side of that line, with varying appetites for small clients. Their published offers are worth reading alongside independent agency reviews before you shortlist.

Check any provider on Companies House before signing. It confirms the legal entity, filing history and whether the trading name matches the contracting company. That step catches white-label resellers quickly.

Membership of the Chartered Institute of Payroll Professionals or the Payroll Software Suppliers Association is a useful signal of training standards. It is not a guarantee of service quality.

Cost factors that decide the answer for London employers

Headcount and churn decide most of it. A bureau charging per payslip punishes high turnover. Software with a banded licence rewards stability.

Pay frequency matters more than employers expect. Weekly payrolls multiply the transaction count and the deadline pressure. Monthly salaried payrolls are the cheapest to run in either model.

Complexity is the second lever. Multiple companies, share schemes, foreign nationals and salary sacrifice arrangements all add work. A bureau prices that work explicitly. Software often needs add-on modules or manual workarounds.

Pay planning affects the budget. If you expect uplifts above inflation, model the employer National Insurance and pension cost now. ONS inflation and price indices give you the planning baseline.

A London employer with 60 staff on monthly pay, one company, no share schemes. In-house software licence around a few thousand pounds a year, plus 0.4 of a payroll administrator's time, plus cover.

A bureau quote for the same payroll typically lands at a monthly retainer with a per-payslip element. The bureau usually wins on total cost once the administrator's London salary is counted.

Software wins if the administrator also does credit control and management accounts.

Decision checklist.

• Count employees, leavers and starters over the last 12 months.
• List every pay frequency and every company entity.
• Identify share schemes, benefits in kind and salary sacrifice.
• Price the internal administrator's time at London market rates.
• Request bureau quotes on the same headcount and frequency.
• Check the processor contract against UK GDPR terms.
• Confirm who files the FPS, the EPS and the declaration of compliance.

If two or more of those items are complex, a bureau is usually the lower-risk route. If the payroll is plain and someone already owns it, software is cheaper. A live payroll software pricing comparison against your own scenario settles the argument faster than any general claim.

Common questions

Is a London payroll bureau more expensive than in-house software? Not always. Once you count the administrator's London salary, pension admin and year-end work, the bureau often costs less for complex payrolls. Software wins on plain, stable monthly payrolls.

Who is legally responsible for RTI submissions if a bureau files them? The employer. The bureau acts as your agent, but HMRC holds you responsible for accurate and on-time submissions. Late filing penalties land on the employer.

Does outsourcing payroll remove our auto-enrolment duties? No. A bureau can run assessments and upload contributions, but the employer remains responsible for compliance with The Pensions Regulator's requirements, including the declaration of compliance.

What data protection terms should a bureau contract include? A written processor agreement covering instructions, security, sub-processors, breach notification and data return or deletion. The employer stays the controller under UK GDPR.

Can we move from a bureau to in-house software mid-year? Yes, but plan a parallel run. You need opening balances, year-to-date figures and a clean handover of P45 and P60 records before the first live payroll.

How do we check a London payroll provider is legitimate? Search Companies House for the legal entity, confirm the trading name, and ask for CIPP or PSSA membership details. Then check references from clients of similar size.