A powerful car bomb outside the London headquarters of the BBC early on Sunday served grim notice on the British capital that dissident Northern Irish guerrillas are waging a new terror campaign.
Police said they believed the Real IRA, responsible for Northern Ireland's worst ever bombing atrocity, was behind the blast aimed at the British state broadcaster. They warned of more attacks to come.
Police were tipped off about the bomb, giving the BBC time to evacuate employees. Only one man was injured.
A bomb disposal unit was attempting a controlled explosion of the device, consisting up to 20 pounds (nine kg) of high explosive hidden in a distinctive London taxi, when it went off, causing a fireball that lit up the night sky in west London.
"It is quite clear we are dealing with ruthless terrorists," Alan Fry, of Scotland Yard's anti-terrorist branch, told reporters. "We, unfortunately, are in a terrorist campaign. I fear that we will see more attacks in coming days and weeks."
Barely 12 hours later, a controlled explosion of another vehicle was carried out, causing the evacuation of London's Victoria railway station. A police source said it was precautionary and no evidence of explosives had been found.
A spokesman for Prime Minister Tony Blair said the dissident group would be hunted down and had no hope of "turning the clock back" on Northern Ireland's peace process.
Over 3,000 people have died in 30 years of violence between Protestants seeking to preserve British rule in Northern Ireland and Roman Catholics backing union with the Irish Republic.
While the Irish Republican Army (IRA) and pro-British "loyalist" militias have maintained a ceasefire since the landmark 1998 Good Friday peace accord, the Real IRA has not.
It secured a grisly place in history with a car bomb that killed 29 civilians in the Northern Irish town of Omagh in 1998 - the province's worst-ever guerrilla bombing.
The BBC's current affairs programme Panorama recently broadcast an investigation into the Real IRA and Omagh. "That undoubtedly...rattled the terrorists," Fry said.
Adjacent to the BBC headquarters is an army reservist base where a bomb disguised as a torch exploded less than two weeks ago, maiming a teenage army cadet.
LINK TO PREVIOUS ATTACKS
Fry said the BBC bombing was part of a campaign started last June when the Real IRA detonated a bomb on Hammersmith Bridge, over the River Thames. He said the group tended not to own up to its attacks. Authorities believe the same "active service unit" blew up rail tracks in the west of the capital last summer.
It has also been linked with a missile attack on the headquarters of the British government's external intelligence agency, MI6, in central London last September.
Coded warnings about the BBC bomb were given to a London hospital and a charity just over an hour before it exploded at 12:30 a.m. (0030 GMT). The same code word had been used before last year's railway line bombing.
Fry said the taxi had been bought from a dealer in north London on Saturday morning by a white male, aged around 30. "He was said to have a Northern Irish accent," he said.
Police were poring over closed circuit television footage of the explosion for clues on Sunday and scouring the area for forensic evidence. Debris was scattered over a wide area.
Political tension is high in Northern Ireland as the peace process appears deadlocked over key issues - scrapping guerrilla arms, reform of the police service and the scaling down of a British military presence.