Image copyright PA Image caption Wreckage from the crash was strewn across the bleak hillside. There were no survivors

Some families of those killed in an RAF air crash on the Mull of Kintyre will travel to Scotland on Sunday to remember the 29 victims on the 25th anniversary.

A Chinook helicopter carrying 25 senior intelligence experts crashed on the remote peninsula on the west coast of Scotland on 2 June 1994.

Leading security personnel from the Royal Ulster Constabulary (RUC), MI5 and the Army died, alongside the crew.

They had been travelling to a security conference in Inverness, just two months ahead of the 1994 IRA ceasefire.

The four crew members who died were from the Special Forces.

A quarter of a century on, the incident continues to raise controversy.

Image caption Chinook helicopters were used regularly to ferry military personnel in Northern Ireland during the Troubles

Fears that the Ministry of Defence (MoD) could be about to destroy archived documents about the crash have recently prompted protests from families of some of the victims, politicians and the Church of Scotland.

Just last week, the church's General Assembly issued a call to the MoD not to destroy the records.

The MoD has said that records closed in 1995 and 1996 will be reviewed for release or disposal this year and a decision will be made in due course.

"Records of significant public and historical interest will be selected for permanent preservation and will not be destroyed," a spokesperson said.

Image copyright Rev Roddy McNidder Image caption Rev Roddy McNidder attended the crash site and remembers the compassion shown by his parishioners

The Reverend Roddy McNidder was present at the crash site on the day and remembers the compassion shown by first responders and local people.

"The people were very much overwhelmed by the incident at the time - it was one of such significance in their lives," he said.

Mr McNidder also spoke of the need to retain the documents held by the MoD.

"The documents became part of the history of the families and the history of Scotland," he said.

The clergyman will lead a service of remembrance at the Mull of Kintyre on Sunday.

Image copyright Susan Phoenix Image caption Susan Phoenix campaigned for better compensation for the victims' families

Ian Phoenix was one of the senior RUC officers who died in the crash.

His wife Susan later campaigned for better compensation for the victims' families.

She had left her husband at RAF Aldergrove earlier in the day and heard a report of the crash on her car radio.

"I remember that feeling of being totally bereft," she said.

Mrs Phoenix is concerned that the remaining documents could be destroyed when potentially life-saving lessons could yet be learned.

She is travelling to the Mull of Kintyre with members of her family this weekend.

Image copyright PA Image caption The pilots, Flt Lt Richard Cook, left, and Flt Lt Jonathan Tapper, were eventually exonerated of blame for the crash following a fresh review of the evidence in 2011

The story of the Chinook cash stayed in the media spotlight for 17 years.

Reviewing the evidence of an initial 1995 RAF board of inquiry, two retired air chief marshals concluded that gross negligence on the part of the two pilots was to blame, but their families led a long campaign to clear their loved-ones' names.

The RAF verdict was criticised in parliamentary committee reports.

Former Brexit secretary David Davis was chair of the Commons Public Accounts Committee in the late 1990s - he told the BBC that clearing the pilots of blame was "a matter of honour".

Image copyright Getty Images Image caption David Davis says clearing the pilots'' names was "a matter of honour"

Mr Davis also expressed support for those campaigning to retain the MoD documents.

"I think they should keep them in case they need to come back to them," he said.

In May 2010, Defence Secretary Liam Fox ordered a review of the evidence.

Pilots Flight Lieutenants Jonathan Tapper and Richard Cook were exonerated of any blame. the following year.

Dr Fox also apologised to the families of both men, who had been wrongly held responsible for the crash.

Image caption The County Antrim coastline in Northern Ireland can be seen 12 miles from the memorial at the crash site

A quarter of a century on the reasons for the crash remain unclear.

The MoD has insisted that, following exhaustive investigations, no evidence was found of technical or mechanical failure.

In 2011, MoD minister Lord Astor said the exact cause of the crash will never be known and pursuing the matter further would only serve to increase the distress of the family and friends of those who died.

A number of memorial events are to be held to mark the 25th anniversary, including a service at Southend Parish Church and at the memorial cairn at the crash site.