SCOTLAND Yard's anti-terrorist chief said last night the bomb which

injured 17 young people at a birthday party at Territorial Army

headquarters in London may have been planted less than an hour before it


The midnight attack in the City was believed to be another IRA strike

on a soft target.

The injured, mostly students, were showered by flying glass and debris

as the blast ripped through a building at the Honourable Artillery


About 30 guests had been celebrating the 21st birthday of Cambridge

law student Mr Mark Venn in another part of the complex, but gathered

for a final drink in the bar just minutes before the bomb exploded on

the roof.

There was no warning, and there has been no claim of responsibility.

But police said the bombing ''has all the hallmarks of the IRA''.

At the scene of the attack in City Road, the head of Scotland Yard's

anti-terrorist squad, Commander George Churchill-Coleman, said the

device was probably a short fuse time bomb rather than a mortar shell or


In a reference to the most likely route of the bombers, through

Bunhill Fields Cemetery, he said: ''We believe that someone gained

access to the outside rear of the building via the cemetery and placed a

timed, controlled device on the roof of the building, possibly within an

hour of the explosion.''

Armed Forces Minister Archie Hamilton said the IRA was terrorising

civilians. ''It is an assault on society as a whole. Everyone of us is

being endangered by these actions.''

Detective Chief Superintendent Derek Willison said the bar was used

most Saturdays, ''presumably by the Territorial Army occupants of the


Mr Angus Gray, 21, from Queen's College, Oxford, a friend of Mr Venn's

from their schooldays at Marlborough, said it had never occurred to any

of the party-goers that they were a target.

''You generally regard soft targets as involving some sort of military

personnel but we were just students and fairly young ones at that,'' he


''One of the blokes I had been talking to had been warned by his

mother to take extra precautions. We were laughing it off.''

Two women, aged 21 and 17, were detained overnight in St Bartholomew's

Hospital, but were not seriously injured. They were expected to be

discharged today. The other 10 women and five men were released after

treatment for minor injuries caused by flying glass.

The Prime Minister said the bombing should invoke ''abject contempt''

for the IRA.

Speaking on the VC 10 just before arriving at Heathrow at the end of

her three-day visit to the Soviet Union, Mrs Thatcher said the IRA

''deliberately kill women and children. They put bombs in a school bus.

They detonate bombs at a Cenotaph memorial service, they bomb Christmas

shoppers. And now they bomb a student birthday party.''

The attack was believed to be the latest in a new mainland terror

campaign by young IRA active service units.

Last Friday one soldier was shot dead and two injured in Lichfield,

Staffordshire. The same evening an Army major was shot dead in Dortmund,

West Germany.

Last month two Australians were mistaken for British soldiers and shot

dead in Roermond, Holland, and a sergeant died and another was injured

when an IRA bomb, planted beneath a van, went off outside an Army

recruiting office in Wembley, north London.