The Co-operative Group could sell legal services from almost 1,000 bank branches, giving it an outlet on nearly every high street in the country following a deal to buy 632 Lloyds TSB and Cheltenham & Gloucester branches.

The group announced this morning that it had agreed to pay £350m upfront for the branches plus an additional £400m based on the performance of the business between now and 2027. The group already owns 330 bank branches, made up of the Co-operative Bank and Britannia Building Society.

The purchase will increase the Co-op’s market share of personal current accounts from 1% to 7%. Its network of almost 1,000 branches will represent 10% of the UK bank network, with 11 million customers.

Co-operative Legal Services is piloting the sale of legal services through 30 bank branches and will roll out the service to the rest of the Bank and Britannia network later this year. The Lloyds takeover could enable legal services to be offered through all 962 branches in England, Wales and Scotland.

However a spokesman for the group said: ‘It will be at least 2013 before the deal [to acquire the new banks] is even implemented. Rolling out legal services to these branches hasn’t been considered yet.’ The group’s chief executive Peter Marks said the deal to buy the banks ‘would deliver the biggest shake-up in high street banking in a generation’.