HR Software Built for UK Employment Law

UK payroll compliance sits at the intersection of HMRC obligations, The Pensions Regulator requirements, and employment law — a combination that creates administrative complexity for businesses of all sizes. PAYE (Pay As You Earn) is the foundational mechanism, but beneath it sits a web of tax codes, National Insurance categories, Real Time Information (RTI) reporting deadlines, and pension auto-enrolment duties that must all operate in synchrony every pay period.

PAYE requires employers to calculate income tax withholding using HMRC-issued tax codes for each employee. Tax codes (1257L is the standard code for 2024/25, reflecting the £12,570 personal allowance) encode each employee's allowances and adjustments. When codes change mid-year — due to a new job, a benefit-in-kind adjustment, or an HMRC amendment — the employer must apply the new code from the date specified. National Insurance contributions run parallel: employees in Category A (the most common) pay 8% on weekly earnings between the Primary Threshold (£242) and Upper Earnings Limit (£967), and 2% above the UEL. Employers pay 13.8% on all earnings above the Secondary Threshold (£175/week), with no upper cap. Space HR maintains current NI category tables and applies changes automatically when HMRC updates thresholds at each fiscal year start.

RTI (Real Time Information) requires Full Payment Submissions (FPS) to be sent to HMRC on or before each payday — not monthly or quarterly. Late FPS submissions attract automatic penalties starting at £100 per month for employers with 10–49 employees. Space HR generates and submits FPS files directly to HMRC's APIs, timestamped before the payroll processing deadline, with confirmation receipts logged in the compliance audit trail.

Workplace pension auto-enrolment applies to eligible employees aged 22–66 earning above £10,000 annually. The minimum contribution rates since April 2019 are 5% from the employee and 3% from the employer, applied to qualifying earnings (between £6,240 and £50,270 for 2024/25). Employers must re-enrol opted-out employees every three years. New employees must be assessed for eligibility and enrolled (or postponed) within their first pay period. Space HR tracks enrolment status for each employee, manages opt-out windows, schedules re-enrolment cycles, and generates pension contribution data files in the format required by major pension providers including Nest, The People's Pension, and NOW Pensions.

IR35 off-payroll working rules affect any UK business engaging contractors through personal service companies. Since April 2021, medium and large businesses in the private sector are responsible for determining whether a contractor's engagement falls inside or outside IR35 using HMRC's CEST (Check Employment Status for Tax) tool. Inside-IR35 determinations require the business to deduct income tax and NI as if the contractor were an employee. Space HR maintains Status Determination Statements (SDS) for all contractor engagements, tracks compliance with IR35 assessment obligations, and processes inside-IR35 contractors through the payroll engine at the appropriate withholding rates — providing a clean audit trail for any future HMRC enquiry.