Buckinghamshire Council has outlined an £11 million plan to move its archives to Tesco in High Wycombe in a bid to stop its archiving licence being revoked.

Tesco’s Newland Street superstore at the Eden Centre will downsize into the ground floor only under a new surrender and renewal agreement with Bucks Council, which owns the building.

A refurbished first floor will house the county’s archives, which have reached capacity at their current home in the council’s Walton Street offices in Aylesbury and no longer meet national standards.

Six temperature and humidity controlled strong rooms at the Aylesbury offices are bulging with shelves and boxes of maps, photographs, electoral registers and other records, including from Victorian workhouses and prisons.

The overflowing treasure trove of historical records – some of which are 800 years old – means that the council is now at risk of losing its provisional archiving licence.

The National Archives has handed the local authority an ultimatum to sort out its cramped storage by November 2024 or risk becoming the first archive service in the country to lose its accreditation.

A council report on its plans for the Tesco reads: “The tenant had intended to vacate the property in its entirety, but following discussions with the council, is willing to downsize into a re-fitted ground floor, on a new occupational lease, vacating the first and part of the second floor.”

The condition of the current archives and lack of expansion space ‘have been an issue for some years’, according to the local authority.

The report adds: “The space no longer meets service needs in terms of customer delivery, audience engagement and, importantly, for the archives it preserves and makes accessible.

“The strongrooms that house the archives are at full capacity and do not meet current standards.

“The lack of suitable storage means the service is unable to meet any future expansion needs and actively limits its ability to collect material reflecting the diversity of the county’s residents.”

The council also proposes relocating Discover Bucks Museum’s collections to Tesco from their main store and HQ in Halton.

It says the resource centre in the village is a ‘poor quality premises’ and could revert back to a school, potentially for children with special educational needs.

The council also said the Halton office is too small to house the archaeological findings that have been unearthed during the construction of the new HS2 high speed railway line through Buckinghamshire.

The Halton resource centre houses a large store of prehistoric, Roman, Saxon, medieval and later archaeological artefacts, as well as natural history and geological collections.

The centre, currently closed to the public, also has a large social history collection, including agricultural equipment, vehicles, furnishings, industrial, personal accessories, clothing and other items.

The plans to relocate historical objects to Tesco from Halton and the Walton Street office – which the council aims to sell – have been approved by cabinet members.

The relocation is estimated to cost £11.26m, which will be paid for by Tesco, the council and existing government grants.

Around £5 million of the budget for the relocation will come from the local authority selling off assets, which it must spend on new assets.

John Chilver, the council’s cabinet member for resources, said: “It is true that we are looking at a number of options regarding the office estate run by the council, including a proposal to relocate the archives to improved accommodation for the longer term.

“However, the whole process is still in its early stages and a lot more work needs to be done before we make any final decisions. We will be fully engaging with any of the services impacted when the time is right.”