A car bomb in Birmingham city centre would have caused "very serious loss of life" if it had detonated fully, police said tonight.
The "substantial" device was the same size as those planted in Ealing - about 40kg - and outside the BBC television centre in west London earlier this year, West Midlands Police said.
It is believed to be the work of the Real IRA, which was blamed for the previous attacks, and was thought to contain more than 30kg of explosives.
Only the detonator exploded, causing no injuries and leaving intact surrounding cars and buildings in the area of New Street railway station.
Speaking at the scene, Birmingham's Assistant Chief Constable Chris Sims said: "This was a very substantial device, similar in size to the devices planted at the BBC and Ealing.
"Fortunately however, the device did not fully detonate. Had it fully detonated in this busy city centre on a Saturday night we would have sustained very serious loss of life and substantial damage to the city.
"This fits a pattern of events involving Irish Republican dissident terrorist groups, probably the Real IRA."
The blast came just hours after politicians in Northern Ireland found a way to rescue the peace process, which was thrown into disarray when David Trimble failed to be re-elected as Northern Ireland’s First Minister.
However the head of the anti-terrorist squad at the Metropolitan Police, Assistant Commissioner Alan Fry, claimed the bomb had been "well planned for some time".
He said: "I doubt if this was opportunists as the situation in Northern Ireland could have been anticipated some time ago - the difficult political situation and indeed the change of name of the police force for Northern Ireland.
"I regret to say that I have been warning for some time that whilst the activity since June 2000 has all been in London, it could happen anywhere on the mainland."
Police forensic teams may be helped because the "home-made" explosive did not detonate, Mr Fry added.
A number of coded warnings were received at 10.13pm but they were "ambiguous and difficult to interpret" and it was too late to deactivate the device.
Earlier, the Chief Constable of the new Police Service of Northern Ireland, Sir Ronnie Flanagan, said the Real IRA was the chief suspect.
He told BBC's Breakfast with Frost programme: "Even though it is at an early stage, we do believe it is a dissident grouping, probably that group that is behind this.
"They want to demonstrate today that they are still there. But I have to say that through all the good work of policing colleagues right throughout the world, thankfully at this stage, although we cannot be complacent about their intentions, their desire far exceeds their ability."
The Taoiseach said he had no doubt the Real IRA was responsible for planting a car bomb which exploded in the English city of Birmingham last night.
"We have got to deal with this on a security basis", Mr Ahern told RTÉ radio, because the dissidents will not listen to reason.
Mr Ahern extended his sympathy to those affected by the bomb which resulted in no injuries.