The families of two Royal Air Force pilots blamed for the military’s worst ever peacetime air disaster have been given new hope of clearing their names after Defence Secretary Des Browne agreed to reconsider their case.

Following a meeting with Lord O’Neill of Clackmannan, spokesperson for the ‘Mull of Kintyre group’ campaigning on behalf of the pilots, Mr Browne will re-evaluate all past evidence, compiled into a single report for the first time.

Speaking after the meeting on 15 January, Lord O’Neill told Channel 4 News: "We now have, we think, a number of points relating to the airworthiness of the helicopter which we think haven't been considered by the MoD."

Taking in new evidence obtained through the Freedom of Information Act, the dossier will also question how "appropriate" the RAF’s legal proceedings have been in regards to the case.

On 2 June, 1994, the four-man crew of an RAF Chinook helicopter and its 25 passengers all died when the flight deviated from its course in poor weather en route from Belfast to Inverness and crashed into a hillside on the Mull of Kintyre.

In addition to the loss of life, the crash was a disaster for military intelligence, with the passengers – all high ranking members of the security services – representing the bulk of British knowledge and experience of the conflict in Northern Ireland.

Cleared by an RAF enquiry, the two pilots – Flight Lieutenants Jonathan Tapper and Rick Cook – have since stood accused of “gross negligence” as a result of having the verdict overturned by two senior officials.

Air Vice-Marshall John Day and Air Chief-Marshall Sir William Wratten, both now retired, failed to give arguments in support of their decision, and have since expressed reservations in regards to their judgement.

All but one of the investigations following their intervention have found in favour of the pilots, including a 1996 Scottish Fatal Accident Inquiry, which stated that "It has not been established... that the cause of the accident was the decision by the crew...to overfly the Mull of Kintyre.”

In 2000, a House of Commons inquiry said: "The unsustainable finding of gross negligence... should be overturned;" a 2002 House of Lords probe agreed.

A 1998 Channel 4 News investigation, the findings of which are included in the dossier, uncovered serious misgivings amongst air crews operating the Chinook fleet prior to the accident.

The investigation featured an audit of the Chinook’s Full Authority Digital Engine Control (FADEC) software, which pilots complained was rolled out for use before being properly tested.

Tony Collins, a writer for trade magazine Computer Weekly, found 486 errors in what was “safety-critical software.

“I was astonished that it related to a helicopter that was in service,” he told the Scotsman on Sunday in 2002.

Both deceased pilots had expressed their concerns regarding the helicopters’ safety to their families, and additional life insurance was taken out by one of the men prior to the accident.

Only the week before, all Chinooks flying out of Northern Ireland’s RAF Boscombe Down had been temporarily grounded due to safety concerns.

Mr Browne has vowed to return his decision within three to five weeks.

Current and former MPs, MSPs and law lords, including prominent Scottish politicians such as Sir Menzies Campbell and Sir Malcolm Rifkind, continue to lobby in favour of Flt Lts Tapper and Cook being cleared.