July 7th: Four bomb blasts on London transport during the morning rush hour kill at least 56 people, including four bombers. Seven hundred people are wounded.
The bombs explode on three Underground trains and a double-decker bus.
July 12th: Police suspect four men, all British nationals.
Police search six houses in and around Leeds, including the homes of three of the four suspects.
Police also seize a vehicle in a car park in Luton, near London, finding some explosives.
July 14th: Thousands of Londoners hold a vigil in Trafalgar Square in the capital.
July 17th: Police release CCTV pictures of all four men walking into a railway station at Luton.
July 21st: Fresh attacks on three London Underground trains and one bus, but bombs fail to explode. One person is injured.
July 22nd: Police mistakenly shoot dead Jean Charles de Menezes, a Brazilian electrician they believed to be a suspected suicide bomber. He was shot at Stockwell Underground station.
July 25th: British police name two of the suspected bombers - Yasin Hassan Omar and Muktar Said Ibrahim (also known as Muktar Mohammed-Said).
July 27th: Police arrest four men in Birmingham - one of whom is Yasin Hassan Omar, wanted in connection with one of the attempted attacks on London's Underground. He is taken to London.
July 29th: Armed police carry out raids in west London and other areas of the city. Reports say two of the suspected bombers have been arrested.
Two people are also arrested at Liverpool Street station. The fourth bomber from July 21st is arrested in Rome, according to reports.