The National Health Service Litigation Authority had admitted liability for the anaesthetic accident at the Westminster Hospital, but had challenged the widow's claim for pounds 15m, plus interest.
Marilyn Plitman, who has remarried since the death of her husband, Joshua Yedid, in 1991, when she was 37, was awarded what is expected to be the largest sum ever made by an English court for a death caused by hospital negligence.
A spokesman for solicitors representing the hospital said the award was not considered a defeat.
"Obviously this will be a burden on the NHS but, on the other hand, it is very considerably less than the pounds 15m, plus interest, that was being claimed."
He said the size of the claim reflected that Mr Yedid was a "very wealthy and high-earning banker".
Mr Yedid, 60, was the vice chairman of the Republic Bank of New York when, in June 1986, he underwent exploratory surgery at the hospital after a bout of internal bleeding.
Because of the anaesthetic problem that occurred, he suffered "catastrophic and irreparable brain damage", which left him in a persistent vegetative state, said Mr Justice Gage at the High Court in London.
He was cared for at various hospitals in London and Israel, but showed no awareness, and died in March 1991.
The NHS had admitted liability, but disputed the damages claim, saying Mr Yedid had died of a heart attack which he might have suffered anyway.
Mr Justice Gage ruled: "On the whole of the evidence, it seems to me that much the most probable cause of death was the persistent vegetative state caused by the defendants' negligence, and I so find."
The judge had been told that the couple and their two sons had enjoyed an affluent lifestyle, with a country house in the Hamptons area of Long Island, and a New York flat.
Lebanese-born Mr Yedid spoke five languages, and was one of the most highly-paid executives of the New York bank. He came to Britain in early 1986 to look after the bank's European operations.
Damages awarded to Mrs Plitman were pounds 1,358,750 for Mr Yedid's loss of earnings up to his death in March 1991; pounds 1,515,625 for her "loss of dependency"; pounds 85,000 for the suffering of Mr Yedid, and a pounds 3,500 sum for statutory bereavement compensation. Today's exchange rates would put the total at almost pounds 3m, but a sum for medical expenses plus interest will still have to be added.Reuse content