Have the police found a fifth bomber?

The third man arrested by police in the armed raid on a house in Tavistock Crescent will be questioned about whether he is the so-called "fifth bomber" who dumped an unexploded device on open ground in west London.

Detectives have been investigating the possibility of a fifth bomber since the discovery of the rucksack bomb, at Little Wormwood Scrubs last Saturday. The site is close to the two addresses in Dalgarno Gardens, in North Kensington and Tavistock Crescent, Notting Hill, where two raids were carried out by police yesterday morning.

The device found at Little Wormwood Scrubs had strong similarities to the other four bombs that failed to go off when detonated - three at Tube stations at Shepherd's Bush, Oval and Warren Street and the fourth on a bus in Shoreditch. It is believed that a fifth bomber may have attempted to detonate his bomb on a bus or a Tube somewhere in London but the device failed to go off and he was not noticed by anyone else. It was then dumped.

The man arrested at Tavistock Crescent was named last night as Wahbi Mohammed, 23, the brother of Ramzi Mohammed, who was arrested at Dalgarno Gardens on suspicion of being the Oval bomber. He was seen being led away by police officers wearing a white overall and was questioned at the high-security Paddington Green police station last night.

Earlier, the area around Tavistock Crescent was cordoned off and some residents evacuated. Neighbours saw police with guns and gas masks enter the premises.

A fifth bombing attempt would make the 21 July bombings a more ambitious attack than the 7 July suicide bombings, which killed 52 people - and which the second attempted attacks had appeared to mirror.