MOTORISTS will be able to judge whether speed cameras in Worcestershire are being used as a "cash cow" when a new study is published next month.

Transport Secretary Alistair Darling announced that the research would compare the number of deaths and serious injuries before and after every camera in the country was installed.

Mr Darling said some speed traps were failing to make roads safer and would have to be ripped out - although he did not reveal where they might be.

The fresh study follows a widely-ridiculed announcement earlier this year which insisted all cameras were in danger hotspots, rather than put up to raise revenue.

Now Mr Darling has been forced to go a step further by publishing exhaustive details of each camera's impact on casualties on a particular road.

Admitting there was an ongoing "controversy", he told MPs: "People can see why the cameras were put there and the difference before and after.

"There will be some sites where it will be necessary for me to say to the local safety partnerships 'Go and ask yourselves whether these cameras ought to be there or whether they should be moved'.

"That is undoubtedly the case, but the vast majority of them do save lives."

The study is being carried out by Department for Transport staff.

It will not reveal how much money each of the 5,000 cameras has raised.

In 2002-03, speed camera partnerships across England and Wales received £73m in fines, of which £7m went to the Treasury.

Earlier this week, the Police Federation warned that officers were being "blamed" by the public for cameras seen as money-makers, rather than safety measures.

The Government announced plans for variable penalties for speeding motorists, with drivers just over the limit given fewer points on their licences.

Damien Green, the Tory transport spokesman, claimed 4,000 cameras were in the wrong places, but the Government had so far failed to identify a single one of them.