The man who made the bombs for the IRA campaign in London which ended with the Balcombe Street siege in December 1975, left a distinctive trade mark on his work, a retired explosives specialist told an Old Bailey jury yesterday.
Mr Donald Lidstone, who was principal scientific officer at the Royal Arsenal Woolwich, at the time of the campaign, said he had examined material from two London bomb factories and from 15 bombing incidents towards the end of 1975.
Bombs left at Locketts Restaurant and in Wilton Street had been defused and had both contained the same sort of timer: a pocket watch with an insulated drawing pin punched through the glass.
Bomb makers were creatures of habit, said Mr Lidstone, and the man who made the two timers had put the drawing pin at the 10 o’clock position in both devices. In material gathered from the bomb factories, Mr Lidstone had found a further 39 watches with drawing pins in the same position.
Mr Lidstone was giving evidence on the third day of the trial of Brian Keenan who is said by the prosecution to have organised the bombing campaign. He denies four charges of conspiring to cause explosions and to possess firearms.
Mr Lidstone said that there were tenuous links between the London incidents and factories and material found at a house in Liverpool. All had signs of Eversoft Frangex, a high explosive made only in the Irish Republic, although Mr Lidstone added that Frangex had also been found at the scene of many other bomb incidents and factories.
The Liverpool and London devices had the same timers made from a watch and a drawing pin. But the Liverpool timers had the pin at 12 o’clock. Irish-made detonators had been found in both cities.
“I couldn’t say that there is a direct connection between the Liverpool explosives and the explosives found at the two addresses in London,” he said. “But I would say that there is a considerable correlation of ideas which come from a common source.”
The trial continues today.