HIDDEN British army marksmen, other than members of the Parachute Regiment on the ground, have been blamed for several of the killings of civilians in Derry on Bloody Sunday 25 years ago, according to forensic and tape recorded evidence highlighted for the first time last night. An investigation broadcast by Channel 4 News claimed that the official Widgery Tribunal of Inquiry into the shooting dead of 13 unarmed civilians and the wounding of 13 more had suppressed, ignored or rejected a range of crucial evidence as to the culpability of the security forces.

Relatives of the Bloody Sunday victims have renewed their calls for a full independent inquiry into the events of January 30th, 1972, as Derry prepares to mark the 25th anniversary of the shootings which the then city coroner, Maj Hubert O'Neill, described ad "sheer, unadulterated murder".

The British government last night rejected the demands for a fresh investigation into the killings.

"There are no plans to set up a further inquiry," a Northern Ireland Office spokesman said.

The new perspective on Bloody Sunday has come from at least three separate sources, which were unveiled on last night's Channel 4 News and are further explored in a detailed new compendium of eyewitness evidence to be published in book form next week.

A key element in the argument that the central conclusions of the Widgery Tribunal were deeply flawed involves detailed tape recordings of British army and RUC radio "traffic" monitored on the day by a prominent radio amateur in Derry.

Mr James de Wint Porter presented full transcripts of his recordings to the Widgery Tribunal which chose, however, to sideline them as having been obtained by "illegal interception", a claim vigorously contested by Mr de Wint Porter.

The recordings indicate that the first three Bloody Sunday victims were probably shot by British army marksmen located high up; ion the old city walls, rather than by the Parachute Regiment unit which had stormed into the Bogside as a civil rights meeting to protest against internment was taking place.

Corroborating evidence by a Derry GP, Dr Raymond McClean who attended the dead and wounded, indicated that the trajectory of the bullets which killed these three was such that they could only have been fired from the area of the walls.

Dr McClean told Channel 4: "I wrote a detailed submission to Widgery and I was told my evidence would not be required ... I just could not believe it."

Dr McClean's assessment was supported on last night's programme by a former British army surgeon, Mr Hugh Thomas.

A compendium of hundreds of eyewitness statements, uncovered and analysed by Mr Don Mullan in a book to be published next Tuesday, reveals at least 45 separate claims by witnesses that shooting took place from the Derry city walls as well as from Parachute Regiment soldiers at ground level.

These statements were also made available to the Widgery Tribunal, but were not explored in evidence. Mr Mullan's book also documents several memoranda, Downing Street minutes and handwritten notes obtained from the Public Record Office in London.

One of these contains the remark that: "LCJ (the Lord Chief Justice, Lord Widgery) will pile up; the case against the deceased ... but will conclude that he cannot find with certainty that any one of 13 was a gunman.

There has never been a formal British government apology for the Bloody Sunday killings, and no soldiers were ever charged in connection with the deaths and injuries.