Campaign groups have welcomed a proposed change in the law allowing police to take blood samples from unconscious drink drivers.

The move is being introduced under David Blunkett's police reform bill.

At present drivers suspected of being over the legal alcohol limit may escape prosecution as they are allowed to sober up before samples are taken.

Now police medical staff will be allowed to take blood samples while drivers remain unconscious.

Home Office minister John Denham said the change was to allow for "rare situations where a drink driver had been involved in a serious accident, but escaped prosecution because they were unconscious for a long time."

The Campaign Against Drink Driving (CADD) was set up by North-East couple Harry and Maria Cope, whose 16-year-old daughter Helen was killed by a drink driver in 1982.

Sarah Anns, a spokeswoman for the group, said: "This should have been done a long time ago.

"Drink drivers escaping prosecution in this way is a big problem and we applaud these new powers."

Police however urged a note of caution. Sergeant Terry Corrigan, chairman of the Durham branch of the Police Federation, said they were concerned that anyone taking such a sample could be open to allegations of assault.

He said the federation was waiting for more detail on the proposed law change.

A Home Office spokesman said: "We believe this is a good safety measure to show people that they cannot get away with drink driving."

Recent figures for the Christmas and New Year period have shown that more drivers are testing positively for being above the alcohol limit.

This was despite a series of police campaigns being launched to warn of the dangers of drink driving.

A total of 6,815 drivers were breath-tested by police in Cleveland, Durham and Northumberland between November 28 and January 2.

Of those, 506 were found to be over the limit.

Nationally the Association of Chief Police Officers (ACPO) said the percentage of drivers testing positively had risen slightly when compared to the 2000-2001 festive period.