Beginning at 8.49 a.m. this morning on the Metropolitan Line between Liverpool Street and Aldgate, a series of co-ordinated blasts have been reported across the transport network in London. Several have been confirmed so far, including a bus in Central London near Tavistock square and further explosions at Aldgate East, Edgware Road, King's Cross, Russell Square and Moorgate stations.

At least two more bus explosions are said to have occurred in Central London and Scotland Yard has declared a major incident on the Underground, which has been completely suspended until further notice.

Hospitals have advised that they are accepting no further non-emergency cases and are said to be on major incident alert, as injuries and casualties are reported across the capital. Exact figures are not yet known.

"The health services are in support to deal with the terrible injuries that there have been," Clarke told reporters outside Downing Street.

He added that, Number 10 was ‘still unsure’ whether the explosions were the result of a terrorist attack and that ministers are meeting to clarify the situation. A statement will be made later today.