Shiraz Butt, 23
Shiraz Butt was born in the West Yorkshire city of Bradford in 1981 and is of Pakistani parentage. Shiraz moved to London to study accountancy and is happily married.

He lived in a house with his wife in the affluent area of Wembley, whilst working as an accountant.

Mr Butt is suspected of the failed attack on the Victoria Line between Oxford Circus and Warren Street.

He was arrested in Bradford on 27 July, on what some believe was a tip off from his younger brother and was the first of the four suspects to be held.

Muktar Said Ibrahim, 27
Muktar Said Ibrahim, also known as Muktar Mohammed Said, is suspected of trying to set off a bomb on a number 26 bus in Hackney.

He came to Britain from Eritrea in 1992, aged 14, as a child refugee and went to school in Edgware, north London.

He applied for British citizenship in 2003 and was naturalised in September 2004.

Mr Ibrahim was arrested in west London on 29 July eight days after the attempted bombings.

Ramzi Mohammed
Mr Mohammed was arrested in west London on 29 July along with Muktar Said Ibrahim. He is suspected of attempting to bomb the Tube near Oval station.

Few details are known about him and his name had not been released prior to his arrest.

Another man arrested at the same time is reported to be his brother, although police have not officially confirmed that.

That man is suspected of being a fifth potential bomber. A device was found in a rucksack in Little Wormwood Scrubs, west London, the morning after the failed attacks.

Osman Hussain, 27
Mr Hussain was arrested in Rome on 29 July and is suspected of trying to bomb a Hammersmith and City Line train at Shepherd's Bush.

He was born in Ethiopia but became a British citizen and he has also been named as Isaac Hamdi.

He was tracked to Rome via his mobile phone and is believed to have left London on 26 July and travelled via Paris, Milan and Bologna.