Speaking to the Today programme on BBC Radio 4 this morning, Clarke said that ID cards wouldn't have prevented the people who planted four bombs which killed 38 people and maimed and injured many others.
The UK government had originally used the terrorist threat to argue for ID cards, but has recently shifted its ground to focus more on the problem of identity theft.
A YouGov survey published last week showed that support for ID cards had dropped to 42 per cent in the UK. The scheme is being attacked on various grounds including cost, the imperfections of the technology, and civil liberties.
The Tube network is equipped with hundreds of close circuit TV cameras, and police will be scanning those records to see if they can find clues to the identity of the perpetrators.
Meanwhile, London buses are running again as are many Tube lines, save for those which have stations which are still being treated as scenes of crime. Details of current disruption and operating services can be found on the Trasport for London site, here. ยต