Lord Healey has become the most senior of British Labour Party figure to call for a halt to the bombing of Afghanistan.
He says continued bombing risks the overthrow of the Pakistani, Saudi and Egyptian regimes.
The former Defence Secretary also says there is the risk of Pakistan's nuclear arsenal falling into the hands of Islamist militants.
In a letter to the British newspaper, The Times, he urged the Prime Minister, Mr Tony Blair, to use his visit to Washington to persuade US President George W Bush to stop the bombing.
His plea is backed by Labour peers Lord Rea and Lord Young and crossbencher Baroness Warnock.
Lord Healey writes: "What are the disadvantages of continuing? More civilians killed; more discord in Pakistan, which could end in fundamentalists getting power and with nuclear weapons at their disposal; possible overthrow of the Saudi and Egyptian regimes and a general flare-up in the Middle East.
"The longer the bombing continues, the greater the danger, while leaving bin Laden untouched in his bomb-proof cave.
"We hope our Prime Minister will join in persuading Washington to stop it."
PA
