An attempted boardroom putsch at HBOS by the former heads of the Bank of Scotland and the Royal Bank of Scotland has been "unanimously" rejected by the board, the bank's chairman has said.

In a letter to Sir Peter Burt and Sir George Mathewson, Lord Stevenson said their proposal to replace him and the bank's chief executive did not form "the basis of any further discussion between us".

The former banking chiefs had earlier written to HBOS calling on its two top men to resign in a bid to bring an end to the planned £12 billion merger with Lloyds TSB.

Lloyds is hoping to deliver annual cost savings of more than £1.5 billion by the end of 2011 as a result of the move - but unions fear that it could be at the expense of thousands of jobs.

In their letter address to Lord Stevenson, the former heads of Royal Bank of Scotland and Bank of Scotland said the rescue takeover was "no longer necessary" given the Treasury's plans to inject cash into UK's creaking banking sector.

Instead, Sir George and Sir Peter proposed taking over at the top of HBOS and drawing up an alternative plan that included keeping the banking group independent.

In a return letter, Lord Stevenson told them: "The board has unanimously concluded that your letter does not form the basis of any further discussion between us."

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