Here are well-regarded outsourced accounting providers you can consider for UK businesses — a mix of global firms that offer high-volume / specialist finance outsourcing and UK-focused specialists that serve SMEs and accounting practices. I’ve noted typical services and strengths so you can match provider → need.

1. KPMG (UK) — Big‑Four global firm with large finance & accounting BPO, transformation and advisory services; strong for complex, compliance‑heavy outsourcing and international businesses. (en.wikipedia.org)

2. PwC / Deloitte / EY — (the other Big‑Four alternatives) offer outsourced accounting, finance transformation, shared‑services and tech-enabled bookkeeping for mid‑market and enterprise clients; good where you need deep industry teams, global delivery and ERP integrations. (See Big‑4 service pages and recent industry coverage.) (en.wikipedia.org)

3. RSM UK — large mid‑market network offering outsourced accounting, payroll, tax and finance transformation; often chosen by growing companies needing personalised partner‑led service with international network support. (outsource-work.com)

4. BDO UK / Grant Thornton UK — full professional‑services firms that provide outsourced bookkeeping, management accounts, tax compliance and finance shared‑services for SMEs and corporates. Grant Thornton has also been active in outsourcing/nearshore delivery models. (ft.com)

5. Moore Kingston Smith / UHY Hacker Young — reputable UK accountancy groups (regional/ national) that offer outsourced bookkeeping, management accounts, cloud accounting (Xero/Sage/QuickBooks) and practice outsourcing for other accountancy firms. Good for UK compliance and partner‑level support. (en.wikipedia.org)

6. QX Global Group / QX Accounting Services — specialist finance & accounting outsourcing provider with long experience serving UK firms and accounting practices (bookkeeping, payroll, year‑end, pack production, reconciliations). Often referenced in “top outsourced accounting firms” lists for the UK market. Good for firms wanting a dedicated outsourced team and offshore/onshore blended model. (outsource-work.com)

7. AdvanceTrack Outsourcing — UK specialist that many accountancy practices use for recurring bookkeeping, payroll and year‑end work. Strong options for firms wanting a managed outsourcing partner rather than one‑off projects. (qxaccounting.com)

8. Specialist offshore/nearshore providers used by UK firms (examples: Exuberant Global, CapActix, Mindspace Outsourcing) — typically lower cost, scalable bookkeeping and back‑office services with experience in UK software (Xero, QuickBooks, Sage) and GDPR/ISO processes where advertised. Good for cost-sensitive SMEs that can accept offshored delivery. (exuberantglobal.co.uk)

9. Marketplace / review data (Trustpilot category snapshots) — for smaller bookkeeping/outsource options, Trustpilot lists many rated bookkeeping services (useful to check client reviews for specific providers and local firms). Use Trustpilot and direct client references to vet quality. (uk.Trustpilot.com)

How to choose (quick checklist)

• Match scale & complexity: Big‑Four or RSM/BDO for complex, regulated or international needs; specialist outsourcers (QX, AdvanceTrack, offshore vendors) for routine bookkeeping, payroll and pack production. (en.wikipedia.org)
• Technology stack: confirm Xero / QuickBooks / Sage / API and ERP integration experience. (mindspaceoutsourcing.co.uk)
• Data security & compliance: ask about ISO 27001, GDPR processes and where work is delivered (onshore vs offshore). (outsource-work.com)
• References & reviews: request references from similar‑size UK clients and check Trustpilot / Google reviews. (uk.Trustpilot.com)
• Pricing & SLAs: compare fixed monthly packages vs per‑task pricing; confirm turnaround times and ownership of working papers.

If you’d like, I can:

• Shortlist 4–6 providers tailored to your business size (SME / scaleup / enterprise) and software (Xero / QuickBooks / Sage), or
• Produce a one‑page comparison (services, typical pricing model, onshore/offshore split, security credentials) for 5 shortlisted firms.

Which would you prefer?