{"name":"UK Payslip Anomaly Index","edition":"2026","permalink":"https://payslipiq.co.uk/anomaly-index","published_at":"2026-05-05","figures_modelled_at":"2026-05-05","presentation_updated_at":"2026-08-05","data_coverage":"Figures modelled at 5 May 2026 using tax year 2025/26 (the most recent complete tax year at publication) and the latest HMRC, ONS and DWP releases available at that date. Not re-estimated for 2026/27.","license":"https://creativecommons.org/licenses/by/4.0/","citation_format":"PayslipIQ Research Team. (2026). UK Payslip Anomaly Index 2026. Retrieved from https://payslipiq.co.uk/anomaly-index. Licensed CC BY 4.0.","publisher":{"name":"PayslipIQ","url":"https://payslipiq.co.uk","press_email":"press@payslipiq.co.uk"},"methodology":["Population baseline of 32.7m UK PAYE workers in tax year 2025/26 (HMRC Income Tax Statistics).","Earnings distribution from ONS Annual Survey of Hours and Earnings (ASHE) 2025.","Job mobility from ONS Job-to-Job Moves dataset and Jobs and Vacancies bulletin.","Marriage Allowance uptake compared with eligible-couples count from ONS Families and Households 2024.","Auto-enrolment participation from DWP Workplace Pension Participation 2024.","Headline figures rounded to two significant figures with stated +/- 15% confidence band.","No proprietary PayslipIQ user data is used in headline numbers; figures derived from public statistics only.","Vintage: all figures as modelled at 5 May 2026 against tax year 2025/26 data; not re-estimated for 2026/27."],"key_findings":[{"headline":"UK PAYE workers on emergency tax code (any month)","value":"~1.5m","sourcing_note":"PayslipIQ analysis from HMRC PAYE RTI volumes + ONS job-mobility rates."},{"headline":"Aggregate annual Marriage Allowance underclaim","value":"~£385m","sourcing_note":"PayslipIQ analysis from HMRC Personal Tax Credits + ONS Families 2024."},{"headline":"Workers between LEL and Primary Threshold (NI risk band)","value":"~2.3m","sourcing_note":"ONS ASHE 2025 + HMRC NI rates."},{"headline":"Eligible jobholders not actively saving via auto-enrolment","value":"9.4%","sourcing_note":"DWP Workplace Pension Participation 2024."},{"headline":"Approx share of new starters defaulted to emergency coding without P45","value":"~1 in 14","sourcing_note":"HMRC starter-declaration guidance + ONS job-to-job flows."}],"categories":[{"id":"emergency-tax-codes","name":"Emergency tax codes","headline_metric":"active emergency-coded workers","headline_value":"~1.5m","description":"Workers on a W1, M1, or X-suffix tax code at a given point in the tax year, derived from HMRC PAYE RTI volumes and ONS job-to-job moves.","primary_sources":[{"name":"HMRC Income Tax Statistics","url":"https://www.gov.uk/government/collections/income-tax-statistics-and-distributions"},{"name":"ONS Jobs and Vacancies in the UK","url":"https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/bulletins/jobsandvacanciesintheuk/latest"}],"estimated":true},{"id":"regional-tax-code-errors","name":"Tax code errors by region","headline_metric":"regional spread of emergency-code rate","headline_value":"0.69% - 1.04%","description":"Regional emergency-coding rates derived from ONS regional employment series and HMRC starter-declaration guidance.","primary_sources":[{"name":"ONS Regional Employment","url":"https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes"},{"name":"HMRC Starter Declarations Guidance","url":"https://www.gov.uk/new-employee/employee-information"}],"estimated":true},{"id":"underpaid-ni","name":"Underpaid National Insurance","headline_metric":"workers in LEL-PT band","headline_value":"~2.3m","description":"Workers in the band where small NI miscalculations can erase a qualifying week of state-pension credit.","primary_sources":[{"name":"HMRC NI Statistics","url":"https://www.gov.uk/government/statistics/national-insurance-contributions-statistics"},{"name":"ONS ASHE 2025","url":"https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/earningsandworkinghours/bulletins/annualsurveyofhoursandearnings/2025"}],"estimated":true},{"id":"auto-enrolment-gap","name":"Pension auto-enrolment compliance gaps","headline_metric":"non-participation rate among eligible employees","headline_value":"9.4%","description":"Share of eligible jobholders not actively saving into a workplace pension despite auto-enrolment, per DWP 2024.","primary_sources":[{"name":"DWP Workplace Pension Participation 2024","url":"https://www.gov.uk/government/statistics/workplace-pension-participation-and-savings-trends-of-eligible-employees-2009-to-2024"}],"estimated":false},{"id":"marriage-allowance-underclaim","name":"Marriage Allowance underclaim","headline_metric":"annual aggregate underclaim","headline_value":"~£385m","description":"Aggregate value of unclaimed Marriage Allowance among eligible UK couples each tax year.","primary_sources":[{"name":"HMRC Personal Tax Credits Statistics","url":"https://www.gov.uk/government/statistics/personal-tax-credits-finalised-award-statistics"},{"name":"ONS Families and Households 2024","url":"https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/families/bulletins/familiesandhouseholds/2024"}],"estimated":true}],"regional_breakdown":[{"region":"North East","paye_workers_millions":1.1,"emergency_code_rate_pct":0.92,"estimated_workers_affected":10120,"note":"Higher seasonal hospitality churn"},{"region":"North West","paye_workers_millions":3.1,"emergency_code_rate_pct":0.81,"estimated_workers_affected":25110,"note":"Mixed urban/rural payroll providers"},{"region":"Yorkshire & The Humber","paye_workers_millions":2.3,"emergency_code_rate_pct":0.78,"estimated_workers_affected":17940,"note":"Manufacturing + agency-heavy"},{"region":"East Midlands","paye_workers_millions":2,"emergency_code_rate_pct":0.74,"estimated_workers_affected":14800,"note":"Logistics workforce volatility"},{"region":"West Midlands","paye_workers_millions":2.5,"emergency_code_rate_pct":0.83,"estimated_workers_affected":20750,"note":"Multi-employment prevalence high"},{"region":"East of England","paye_workers_millions":2.7,"emergency_code_rate_pct":0.69,"estimated_workers_affected":18630,"note":"Lower job-to-job moves"},{"region":"London","paye_workers_millions":4.5,"emergency_code_rate_pct":1.04,"estimated_workers_affected":46800,"note":"Highest job-mobility region (ONS)"},{"region":"South East","paye_workers_millions":4,"emergency_code_rate_pct":0.71,"estimated_workers_affected":28400,"note":"Stable PAYE base"},{"region":"South West","paye_workers_millions":2.4,"emergency_code_rate_pct":0.86,"estimated_workers_affected":20640,"note":"Seasonal tourism distortion"},{"region":"Wales","paye_workers_millions":1.3,"emergency_code_rate_pct":0.79,"estimated_workers_affected":10270,"note":"Public-sector heavy mix"},{"region":"Scotland","paye_workers_millions":2.5,"emergency_code_rate_pct":0.83,"estimated_workers_affected":20750,"note":"Includes S-prefix Scottish codes"},{"region":"Northern Ireland","paye_workers_millions":0.8,"emergency_code_rate_pct":0.88,"estimated_workers_affected":7040,"note":"Smaller PAYE base, higher variance"}],"year_over_year":[{"metric":"Estimated active emergency-coded workers (any month)","value_2024":"~1.4m","value_2025":"~1.45m","value_2026":"~1.5m","unit":"workers","notes":"Tracks job-to-job mobility (ONS)."},{"metric":"Marriage Allowance aggregate underclaim","value_2024":"~£420m","value_2025":"~£400m","value_2026":"~£385m","unit":"GBP/year","notes":"Slow narrowing as awareness grows."},{"metric":"Workplace pension participation among eligible employees","value_2024":"90.0%","value_2025":"90.3%","value_2026":"90.6%","unit":"%","notes":"DWP series, modest improvement."}],"sources":[{"name":"HMRC Income Tax Statistics and Distributions","url":"https://www.gov.uk/government/collections/income-tax-statistics-and-distributions","publisher":"HMRC","year":2025},{"name":"HMRC National Insurance Contributions statistics","url":"https://www.gov.uk/government/statistics/national-insurance-contributions-statistics","publisher":"HMRC","year":2025},{"name":"HMRC Personal Tax Credits Statistics","url":"https://www.gov.uk/government/statistics/personal-tax-credits-finalised-award-statistics","publisher":"HMRC","year":2025},{"name":"ONS Annual Survey of Hours and Earnings 2025","url":"https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/earningsandworkinghours/bulletins/annualsurveyofhoursandearnings/2025","publisher":"ONS","year":2025},{"name":"ONS Jobs and Vacancies in the UK","url":"https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/bulletins/jobsandvacanciesintheuk/latest","publisher":"ONS","year":2026},{"name":"ONS Families and Households 2024","url":"https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/families/bulletins/familiesandhouseholds/2024","publisher":"ONS","year":2024},{"name":"DWP Workplace Pension Participation 2024","url":"https://www.gov.uk/government/statistics/workplace-pension-participation-and-savings-trends-of-eligible-employees-2009-to-2024","publisher":"DWP","year":2024}],"attribution":"PayslipIQ analysis based on publicly available HMRC + ONS data. Free to cite under CC BY 4.0."}