Police believe may have found a link between the people that carried out the failed bomb attacks on the London transport system last week and the group that succeeded in detonating four explosives and killing 52 people in the British capital two weeks' ago.
The news follows their admission yesterday that they had mistakenly shot and killed a Brazilian in south London on Friday. The Metropolitan Police Service said the incident in which Jean Charles de Menezes was shot five time by a plain clothes officer at Stockwell underground station was a "tragedy".
The force had come in for considerable criticism even before it emerged the victim was not a terrorist, and police are in need of a breakthrough in their two-week old investigation in to the first bombings to boost public confidence.
Security sources in today's British press, say two of the July 7th bombers attended a whitewater rafting trip at the same centre in Wales as some of the July 21st bombers.
This was based on evidence discovered in rucksacks left behind by the failed bombers. Detectives believe the trip could have been used as a bonding exercise.
Metropolitan Police Commissioner Sir Ian Blair this afternoon said there were similarities between the explosives used in Thursday's failed bomb attacks and those detonated July 7. But he said investigators still had no proof the two strikes were linked.
When asked if Thursday's attacks were connected to those of July 7th, Sir Ian replied: "We have no proof that they are linked but clearly there is a pattern here."
Police have made two arrests after Thursday's botched attacks. Officers have not released the identities of those detained.
But Sir Ian added that officers were "still anxious for any sighting of the four individuals" who carried out Thursday's strikes. Closed-circuit TV stills of the suspects were made public last week.
Police carried out several controlled explosions to dispose of a suspect package found in northeast London, which they said may have been linked to devices used in the botched July 21st attacks. They refused to elaborate.
The Abu Hafs al Masri Brigade, an al Qaeda-linked group, has claimed responsibility for Thursday's bombing attempts and those of July 7th, but the group's claims of responsibility for previous attacks in Europe have been discredited by security experts.
Police yesterday also revealed a huge response to the publication of CCTV images of the four suspects wanted in connection with last week's bombings. They received more than 500 calls and 80 e-mails since releasing the images.
The four men are being hunted in connection with Thursday's attempted bomb attacks on underground trains at Oval, Warren Street and Shepherd's Bush and on a number 26 bus in Shoreditch.
Police recovered rucksack bombs from all four sites. None of them detonated properly and there were no serious injuries but the strategy for the attacks was an almost exact replica of the July 7th bombings which killed 52.
Meanwhile, Scotland Yard confirmed that a "suspicious package" had been found in north west London which may be linked to the four bombs recovered in the wake of Thursday's attempted attacks.
The package was found by a member of the public in bushes in Little Wormwood Scrubs. Police said it would be subject to "detailed forensic analysis".
Two men arrested in Stockwell in connection with the attempted attacks were still being held at the high security Paddington Green police station.
Police have so far raided three addresses - one in West Kilburn, another in Stockwell and one in Streatham Hill - in connection with the investigation.
London's Mayor Ken Livingstone argued that terrorism was an international scourge that could strike anywhere and he was dismissive of the decision by Italian soccer club Inter Milan to cancel a pre-season tour of England.
"I think that it is a very silly thing to do because it is playing the terrorists' game. They want to change the way we live. The terrorists, I am sure, will be celebrating their decision," he said.