The verdict in three sentences
For a London mid-sized company, legally admissible electronic archiving is no longer optional: payroll records kept 3 to 6 years, VAT and company accounts 6 years, contracts 6 to 12 years after they end, some pension and health records far longer. You have two routes: a managed archiving provider charging GBP 0.40 to 1.70 per GB per month, or a custom system at GBP 26,000 to 60,000 aligned with BS 10008 and ISO 14641, using qualified timestamps, delivered in 3 to 5 months. The right choice depends on volumes, business integrations and how much control you need.
Retention periods and technical requirements
Evidential weight rests on integrity, traceability and durability. BS 10008 (UK) and ISO 14641 (the international equivalent of France's NF Z42-013) set the requirements: cryptographic hashes, sealed audit log, durable formats such as PDF/A, exit rights.
| Record | Retention period | Basis | Key requirement |
|---|---|---|---|
| Payroll and PAYE records | 3 years after tax year, 6 recommended | HMRC rules | Accurate retrieval for audits |
| Customer and supplier invoices | 6 years | VAT and Companies Act | Integrity, legibility |
| Company accounting records | 6 years (private companies) | Companies Act 2006 | Retrieval on request |
| Simple contracts | 6 years after end | Limitation Act 1980 | Signature and timestamp |
| Deeds | 12 years after end | Limitation Act 1980 | Long-term integrity |
| Personnel files | 6 years after departure | Common practice, UK GDPR | Confidentiality |
| Pension and certain health records | Up to 40 years | Sector regulations | Permanent readability |
Managed provider or custom: the numbers
| Criterion | Certified managed provider | Custom build by Kolonell | HR document vault SaaS |
|---|---|---|---|
| Initial cost | GBP 1,700 to 8,500 integration | GBP 26,000 to 60,000 | GBP 850 to 4,300 |
| Recurring cost | GBP 0.40 to 1.70 per GB per month, plus fee | GBP 3,400 to 7,700 maintenance a year | GBP 0.85 to 2.60 per employee per month |
| BS 10008 / ISO 14641 | Covered by provider | Designed to comply, certification optional (GBP 13,000 to 26,000) | Depends on vendor |
| Qualified timestamping (UK eIDAS) | Included | Via qualified provider, GBP 0.02 to 0.09 per token | Included |
| ERP, HRIS, DMS integration | Standard connectors | Custom, close to your flows | Payroll only |
| Timeline | 1 to 2 months | 3 to 5 months | 2 to 6 weeks |
| Exit rights | Contractual, sometimes costly | Full, you own code and data | Variable |
A managed provider suits modest volumes. Custom becomes cost-effective when volumes exceed several TB, when records come from many internal systems or when you need fine business search (by client, contract, employee number).
What a custom project includes
| Work package | Content | Indicative budget (GBP) |
|---|---|---|
| Scoping and retention policy | File plan, periods, roles | 3,400 to 6,800 |
| Ingest and sealing engine | SHA-256 hashes, chained log, PDF/A | 6,800 to 15,500 |
| Qualified timestamps and signatures | Integration of a qualified provider | 2,600 to 6,000 |
| ERP, HRIS, DMS connectors | Automatic ingest | 5,100 to 15,500 |
| Search, retrieval, disposal | Search engine, controlled disposal | 4,300 to 10,300 |
| Security and UK hosting | Encryption, dual site, access logs | 3,400 to 6,000 |
Mini case study
Claire, compliance lead at a 1,200-employee London company, stores 18 TB of records, growing 3 TB a year. With a managed provider at GBP 1.00 per GB per month, the bill reaches about GBP 221,000 a year from year one and rises with volume. A custom system at GBP 51,000, plus GBP 6,800 maintenance and GBP 10,300 a year of encrypted dual-site object storage, costs about GBP 68,000 in year one, then around GBP 17,000 a year. Over 5 years the gap exceeds GBP 900,000. For 300 GB, however, the managed provider remains cheaper.
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FAQ
How much does legally admissible archiving software cost in 2026?
A custom build costs GBP 26,000 to 60,000, plus GBP 3,400 to 7,700 a year in maintenance. A managed provider charges GBP 0.40 to 1.70 per GB per month.
Is BS 10008 mandatory?
No, but it is the reference courts and auditors recognise. Designing to it from the start costs far less than retrofitting compliance later.
Is plain cloud storage enough?
No, storage without hashes, a sealed log or timestamps cannot prove integrity over time. In a dispute, the record may be challenged.
How long does deployment take?
Allow 3 to 5 months for custom, including 3 to 4 weeks of scoping. Payroll and accounting connectors are usually delivered first.
What about e-invoicing?
The system archives structured invoices (UBL, Peppol) for 6 years as the UK moves towards mandatory e-invoicing. This connector adds GBP 2,600 to 5,100 to the budget.
Let's scope your project. Share your volumes, record types and source systems for an estimate and a 3 to 5 month plan. 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.
