Get the latest updates as we post them — right on your browser

. Last Updated: 07/27/2016

London IRA 'Duds' Held Largest Charge in History

LONDON -- Two suspected Irish Republican Army bombs designed to blow up one of London's busiest bridges probably contained the most amount of high explosives ever used on the British mainland, police said Thursday.

Police said the bombs, left in two briefcase-style boxes under Hammersmith Bridge in southwest London, contained "upwards of 30 pounds [14 kilograms] of high explosives."

The detonators went off without igniting the bombs at about 2150 GMT on Wednesday. No one was hurt as police had cleared the area after a telephone warning.

"This is probably the largest amount of high explosives ever to have been placed on the mainland," a police spokesman said.

"These would have caused a very large explosion, and there is no doubt that this was meant to kill, cause injury and major structural damage."

Detectives had thought the blasts were warning shots by the IRA to mark the 80th anniversary of the Easter Uprising against British forces in Dublin, one of the hallowed events in the history of Irish rebellion.

But the size of the bombs showed that the guerrilla group, which broke a 17-month cease-fire with a huge blast in February in east London, was ready to escalate its armed campaign to oust British forces from Northern Ireland.

It was the second IRA attack in a week and the sixth since the IRA's cease-fire ended.

If the bombs had gone off, they would have paralyzed traffic into the British capital across the Thames. The recently restored Victorian bridge, one of the most fragile in the capital, is used by 30,000 rush-hour commuters every day.

The IRA in the past has used a truckload of fertilizer with a Semtex high-explosive detonator for its bomb attacks.

Wednesday's bombing attempt also marked the third anniversary of a massive bomb in London's financial district that killed one man and caused millions of dollars in damage. Police with sniffer dogs cleared the area after a news agency received a coded warning. Local residents were told to keep away from their windows for fear of shattered glass.

Resident Christine Albrow said, "It's a terrible shock to think they are targeting the bridge. I walk over it every day with my son. It is our lifeline to London."

The detonators went off only hours after the IRA's political wing, Sinn Fein, ended weeks of uncertainty by confirming it would participate in Northern Ireland elections planned by Britain as a prelude to vital peace talks.

Britain reacted by reaffirming Sinn Fein would be barred from the June talks unless the IRA called off a 25-year war to end London's rule over the province and unite Ireland.

Sinn Fein strategist Martin McGuinness warned there was "no prospect whatsoever" of a new IRA cease-fire unless Republicans were convinced there were going to be real peace negotiations.

The first bomb that shattered the truce on Feb. 9 in London's Docklands district killed two people and injured 100. It was made of half a ton of fertilizer, fuel oil and Semtex high explosive.

Police destroyed a second bomb in a telephone booth 10 days later, and an IRA guerrilla killed himself and blew up a bus, injuring several other people, while carrying another bomb, made of 2.3 kilos of Semtex.