Anti-terrorist investigators in London Saturday described the public response to calls for possible clues about the Irish Republican Army's mortar attack on the British war Cabinet as "magnificent."

A spokeswoman for Scotland Yard said "hundreds" of calls had been received since an anti-terrorist hotline was set up soon after Thursday's attack."It's a magnificent response," she said. "Just great."

In the attack, a bomb was lobbed into a garden behind 10 Downing Street, where Prime Minister John Major was meeting with top government officials.

Major, describing the attack in a speech Saturday in Scarborough, 200 miles north of London, said, "It happened very speedily."

"We were in the middle of a discussion on the (Persian) Gulf and suddenly (there was) a very remarkable explosion and the windows appeared to buckle in the cabinet room," Major told a gathering of the Young Conservatives political group.

"Certainly it darkened outside, there were some secondary explosions and it was perfectly clear immediately what it was," he said. "So the sensible thing to do was to move from that room to another and carry on with our work."

The outlawed IRA, claiming credit for the attack, warned the Cabinet "will have to meet in bunkers" until Britain withdraws from Northern Ireland and the region is united with the Irish Republic.

Detectives were interviewing civil servants and others who were in the area when a white Ford van was abandoned at the intersection of Whitehall near Horse Guards Avenue, seconds before three rockets were fired through a hole in the roof of the van. Two police officers and two civilians were slightly wounded.

Scotland Yard established the van was bought in London in July by three men who paid cash, but it could have changed hands since then.

Investigators also called for help from specialist metal dealers who may have unknowingly provided components for the mortars.