The UK’s financial regulator is thought to have sounded out potential “white knights” for Bradford & Bingley as part of its contingency planning in the event that Britain’s biggest buy-to-let lender is buffeted by further market turmoil.

The Financial Services Authority, responsible for ensuring the stability of the UK’s financial system, is thought to have dusted off back-up plans on B&B following last week when Lloyds TSB, the UK’s fourth largest bank, had to step in to rescue HBOS, the UK’s biggest mortgage lender.