The death toll from Britain's big freeze is continuing to rise, taking the number of lives lost to seven.

Two men were killed in a motorway crash on the M62 in Humberside and two teenage girls died when their Peugeot 206 collided with a Royal Mail box van in Cumbria.

The men, aged 30 and 56 and both from Nottinghamshire, were travelling in freezing conditions on the eastbound carriageway between junctions 35 and 36 at 11.50am yesterday when the crash happened. Their silver pick-up truck was in collision with a white lorry.

The lorry driver, a 36-year-old Manchester man, was arrested on suspicion of causing death by dangerous driving, Humberside Police said.

It also emerged that the two girls' deaths occurred in treacherous road conditions, which police said could have contributed to the tragedy. Grace Simpson and Jessica Lakin, both 19, were killed on the A595 in Carlisle.

A Cumbria Police spokesman said: "The treacherous road conditions appear to have been a factor in this collision."

Earlier in the week two Cumbrian pensioners in Kirkby Stephen and Workington died after falling in their gardens where they spent hours lying in sub-zero temperatures until they were found. And a good Samaritan who stopped his car to help a stranded motorist in the Yorkshire Dales was killed when he was struck by another vehicle.

A 14-year-old girl was airlifted to hospital on Friday night after she was hit by falling ice from the roof of her house. Samantha Kinghorn, from Gordon, Berwickshire, was taken to Glasgow Southern General's spinal unit where she was described as being in a "serious but stable" condition.

Saturday's marginally warmer weather has provided something of a reprieve with an unexpected thaw across the south of England - though forecasters said next week will remain very cold.

Billy Payne, of Meteogroup, the Press Association's weather arm, said: "Today is probably going to be the warmest. Into next week temperatures drop away again and lots of areas could be struggling to reach zero degrees and there will be sharp frosts. It is still very cold into next week but from Wednesday onwards there could be a slight recovery."