08.49 - Emergency services called to London's Liverpool Street Station after reports of an explosion on the Metropolitan Line between Liverpool Street and Aldgate. Reported as "some kind of power surge".

08.50 - Police called to Aldgate station, east London.

09.22 - King's Cross, Liverpool Street and Aldgate stations cleared.

09.31 - The incident caused major disruption to the entire network with stations across the capital being closed.

09.33 - London Underground said that there has been "another incident at Edgware Road" station in north west London.

09.53 - Mainline train company First Great Western said its services into London's Paddington station were terminating at Reading in Berkshire because of the Underground crisis.

10.00 - The National Grid, which supplies power to the Underground, said there had beenno problems with its system this morning which could have contributed to the incidents.

10.13 - Union officials said their sources had told them there had been at least one explosive device on the Underground. One explosion happened at Edgware Road and there were suggestions of two other explosions at King's Cross and Aldgate.

10.14 - Reports of a bus being ripped apart in an explosion in central London.

10.19 - Mainline services were being halted short of London. The Silverlink company, which normally operates into Euston station, was terminating trains at Watford Junction in Hertfordshire.

10.32 - Mainline London to Scotland train company GNER said it did not expect its East Coast Main Line services to run as far as London at any time today.

11.02 - Home Secretary Charles Clarke confirmed that there had been "terrible injuries" in the explosions across London.

11.24 - Mobile networks report delays for people trying to get through to friends and relatives, after a surge in the volume of calls.

11.30 - Met Police Commissioner Sir Ian Blair said: "We are not aware of any warning at the moment. We have concluded that this is a co-ordinated attack."

11.51 - St Mary's Hospital said it had received four critically injured patients, eight seriously hurt and 14 with minor injuries so far. It could confirm no deaths and had treated no children.

12.00 - Tony Blair says: "It is reasonably clear that there have been a series of terrorist attacks in London."

12.01 - A spokeswoman for University College Hospital in central London, near the scene of the Russell Square bus blast, said: "We have started to receive casualties but we cannot say how many."

12.05 - Reports that the Stansted Express rail service is suspended, although flights are operating normally at Stansted airport in Essex.

12.16 - Emergency services called to Leicester Square underground station, a spokesman for the London Ambulance Service said.

12.21 - More than 100 casualties and one of the dead were taken to the Royal London Hospital in Whitechapel. Three double-decker buses loaded with casualties had brought the injured to the hospital.

12.30 - 54 patients have been taken to the Royal Free Hospital in Hampstead, north London.Two of those were taken into theatre, said a hospital spokeswoman. Six are described as major injuries, two more are in high dependency and one is in X-ray. Two of the 54 were children but their condition is not thought to be serious.

12.36 - A British Transport Police spokeswoman said it had no knowledge of any reports of an explosion at Leicester Square.

12.45 - Superintendent Jon Morgan of the Metropolitan Police said there had been a number of fatalities as well as serious casualties at Edgware Road station. All the dead and injured have been moved from the scene, which is now being examined forensically.

12.51 - A spokeswoman for Guy's and St Thomas' hospital said eight casualties, some critically injured, were being cared for so far.

12.51 - Scotland Yard confirmed that seven explosions have been reported in four sites. The first site is around Russell Square and Kings Cross Underground stations. The second is the area including Moorgate, Aldgate, and Liverpool Street Underground station. The third is Edgware Road Underground and the fourth is Tavistock Square, where a bus was ripped apart by a blast.

13.01 - Al Qaeda terrorists claimed responsibility for the London blasts on an Islamic website and said: "Britain is now burning with fear, terror and panic in its northern, southern, eastern, and western quarters."

13.03 - Metropolitan Police deputy assistant commissioner Brian Paddick said initial reports were that 150 people had been seriously injured in the blasts. "It does appear from the information we have at the moment that these were caused by explosives but we are awaiting forensic confirmation of that."

13.25 - Royal London Hospital said they'd received 183 patients from two of the incidents. Eight were critically injured, including one who was brought in in cardiac arrest. Six people were being operated on. Some 123 of the 183 patients had already been discharged.

13.25 - Prime Minister Tony Blair boarded his helicopter to leave the G8 Summit at Gleneagles and return briefly to London, Downing Street said.

13.27 - US President George Bush said from the G8 summit in Gleneagles: "We condemn utterly these barbaric attacks. We send our profound condolences to the victims and their families."

13.30 - Network Rail said the Victoria, King's Cross, Liverpool Street, St Pancras and Euston mainline London stations were still shut.

13.32 - Great Ormond Street Children's Hospital said they were currently operating on two seriously injured patients.

14.09 - St Mary's Hospital said it had received 36 casualties, of whom six are critically injured, 17 seriously injured and 13 have minor injuries.

14.12 - Some of the 70,000 workers at Canary Wharf in London's Docklands were allowed to leave early because of the travel chaos caused by the explosions.

14.18 - A Transport for London spokeswoman said the bus hit by the explosion was a number 30, travelling from Hackney to Marble Arch.

15.00 - Euston and Paddington stations have re-opened. A spokesman for Network Rail said: "We hope to open St Pancras and Liverpool Street soon and also plan to start King's Cross's suburban services.

15.05 - Scotland Yard issues the following casualty hotline number 0870 1566 344.

15.19 - Westminster City Council announces all 54 state schools in Westminster will be closed tomorrow in the wake of the terrorist bombings and resulting public transport chaos.

15.25 - In a press conference, police confirm at least 33 people have been killed in the blasts across London.

Officials confirm seven were killed when an explosion went off on a Central or Circle Line train 100 yards into a tunnel from Liverpool Street at 08.51.

15.26 - Police say at 08.56, an explosion in a Tube train at King's Cross/Russell Square killed 21 people.

15.27 - Police say at 09.17, an explosion at Edgware Road blew a hole through a wall. Three trains were involved. Five people were killed.

15.28 - Police say that at 09.47, an explosion ripped apart a bus at Upper Woburn Place, near Euston station. They say there were fatalities, but are unable to confirm the figure at this time.

15.29 - Police say no warning was given for the attacks.

16.30 - The Union Jack flying at Buckingham Palace lowered to half-mast, at the Queen's request, in a mark of respect for the dead and injured.

16.50 - Union Flag will be flown at half-mast on all Government buildings tomorrow, it is announced by the Government.

17.13 - Union sources said the number 30 bomb blast bus was on diversion after it emerged the driver had stopped to ask the name of the street, shortly before the vehicle exploded.

17.26 - UN Secretary General Kofi Annan said he was "devastated" by the attacks.

17.33 - A grim Tony Blair pledges Britain will not be intimidated by the string of terrorist bombings which killed at least 33 people in London.

18.19 - Transport Secretary Alistair Darling vows to restore London's transport system as soon as possible.

18.26 - Police said the number of fatalities stood at 37. They confirmed two people had died on the bus near Euston station.

18.45 - Some main line services at King's Cross and Liverpool Street resume operations.