Campaigners from the Mull of Kintyre Group believe they have uncovered new evidence challenging the findings of an RAF Board of Inquiry which blamed "gross negligence" by the pilots.

All 29 people on board the helicopter - including 25 leading figures involved in Northern Ireland security - were killed when it crashed into the Scottish island in bad weather on June 2 1994.

Senior Labour peer Lord O'Neill of Clackmannan, who will present the report to Mr Browne, said that they believed that it included evidence which was not available to the Board of Inquiry.

Campaigners, including the parents of the pilots - Flight Lieutenants Jonathan Tapper and Rick Cook - have long argued that problems with the Chinook's engine control software could have been a factor in the crash.

The Ministry of Defence has said that the agreement by Mr Browne to receive the report did not mean that he had agreed to a full review of the case.