The Royal National Lifeboat Institution (RNLI) is set to receive a multimillion-pound windfall after two classic Ferraris were left to the charity in a will.
Northamptonshire businessman Richard Colton's dying wish was for his cars to be sold to fund the building of a new lifeboat named after himself and his late wife Caroline.
The cars are a 1960 Ferrari 250 GT SWB and a 1967 Ferrari 275 GTB/4.
They will be sold by auction house H&H Classics, which said sales of similar Ferraris fetched a total of around £8 million.
Guy Rose, legacy manager at the RNLI, said: "We are deeply grateful and humbled by Mr Colton's generous gift and his decision to benefit the RNLI in this way.
"Six out of every 10 lifeboat launches are only made possible because of gifts left to us in wills, so they are vital to saving lives at sea.
"Mr Colton's generosity will be felt most by our volunteer crews and the people whose lives they save."
The sale will take place at the Imperial War Museum Duxford, Cambridgeshire, on October 14.
Simon Hope, chairman of H&H Classics, said: "We are honoured to have been chosen to handle this sale which is of national significance.
"These stunning motor cars have been with Richard Colton for 40 years and meant a very great deal to him so we are absolutely committed to realising the maximum amount for the cars. It promises to be an historic sale."
Mr Colton, who was involved in the footwear industry, was described by close friends as a shy and private man and was known to be nervous of the sea.
He died in March aged 82.