Defence Secretary Liam Fox has apologised to the families of two RAF pilots who were wrongly blamed for the 1994 Chinook helicopter crash.
Two RAF air marshals had accused Flt Lts Jonathan Tapper and Richard Cook of gross negligence over the crash on Mull of Kintyre in which 29 people died.
But a fresh review found they should not have been blamed and the earlier ruling has now been set aside.
Mr Fox said he hoped this would remove any stain on the pilots' reputations.
Campaigners have spent almost two decades trying to overturn the decision to blame Flt Lts Tapper, from Norfolk, and Cook, from Hampshire, for the crash.
They claimed that the Chinook helicopter had suffered many technical problems.
The helicopter was carrying 25 of Britain's most senior intelligence experts from Northern Ireland to a conference in Inverness.
All 29 people on board, including the four special forces crew, died when the Chinook crashed on the Mull of Kintyre, on the west coast of Scotland.
After an RAF board of inquiry found the most probable cause was the selection of the wrong rate of climb, a report by two air marshals - Sir William Wratten and Sir John Day - concluded the pilots were "negligent to a gross degree".
However, a Scottish fatal accident inquiry concluded it was impossible to establish the exact cause of the crash.
The RAF verdict was also criticised in separate House of Commons and House of Lords committee reports.
Successive defence secretaries resisted pressure to reopen the case, but in May last year, Dr Fox announced he was ordering a review of the evidence.
Retired judge Lord Philip, sitting in private along with a panel of three Scottish politicians, has spent nine months reviewing the accident.
He concluded that: "Because of the limited amount of evidence available, the investigating board were unable to determine the cause of the accident, and so concluded that it was impossible to find that the pilots had been negligent to any degree.
"The reviewing officers, on the other hand, concluded on the same evidence that both pilots had been negligent to a gross degree.
"We have unanimously concluded that the high standard of proof did not allow the reviewing officers to make that finding on the basis of the available evidence."
Lord Philip's review recommended that the finding of gross negligence should be set aside.
It also said that the Ministry of Defence should reconsider its policy and procedures for the transport of personnel whose responsibilities are vital to national security.
Lord Philip added that it was "regrettable" that the MoD had adopted an "intransigent stance" to calls to reconsider the findings.
Following Lord Philip's findings, Mr Fox told the House of Commons that he had now written to the relatives of the airmen to apologise for the distress caused to them by the RAF's original findings that they were guilty of "gross negligence".
He told the Commons: "I hope that this report, and the action I have taken in response to it, will bring an end to this very sad chapter by removing the stain on the reputations of the two pilots."
Professor Peter Watson, who represented the family of Flt Lt Richard Cook, said the findings of the inquiry largely reflected the conclusions of the fatal accident inquiry in 1996.
"It also reflects what the initial RAF investigation found - namely, that there was no basis to hold the pilots negligent," he said.
"The initial Board of Inquiry findings were ordered to be altered by senior officers who had not taken part in the inquiry. Many will find this extraordinary."
He added: "The version of the Chinook which crashed had been newly introduced to service and had suffered many technical problems. Indeed, the RAF themselves pursued claims for compensation arising from faults.
"Those who ordered a finding of gross negligence have now been shown to have acted wrongly. They need to explain their conduct, which has caused such hurt to the families and damaged the reputation of two fine pilots."