SOME speed cameras will continue to be hidden - despite a Government pledge that they must be painted yellow to alert motorists.

But in Wiltshire it is likely that the cameras will remain high profile.

Ministers have told police forces they will be allowed to install difficult-to-see grey cameras if they have good reason for obscuring them.

The announcement has been hailed as a victory by Transport 2000, which had condemned the moves to make speed cameras more visible.

However, it has not been welcomed by motoring organisations who fear it will allow police to use speed cameras as a "cash cow" to raise extra funds.

Wiltshire's force was told its cameras must be painted yellow in return for permission to spend the cash raised on new cameras and film.

Now the Government has been forced to clarify the rules in the face of an aborted court challenge by Transport 2000 and other road safety campaigners.

A joint statement said: "There is nothing to prevent any police force from asking the Secretary of State to amend the rules, or allow an exception to them, to permit flexibility."

David Frampton, of Wiltshire Constabulary's Central Road Safety Unit, said: "I can't see any case where we would think it beneficial to employ covert cameras.

"The whole idea of speed cameras is to make them visible and to slow people down." Vicky Cann, assistant director of Transport 2000, said: "Covert cameras send drivers the message that, just because you can't see a camera, that doesn't mean that there isn't one.

"This should encourage drivers to stick within the speed limits, thereby reducing the death toll on our roads."

But an RAC spokesman said: "The problem we have with hidden speed cameras and those painted grey is they encourage sharp braking, which can be very dangerous."

John Spellar, the transport minister, denied there had been a government U-turn, insisting police forces had always had the right to request an exemption.

He said: "To date, we have only ever received exemption requests on grounds of the location being in an area of outstanding natural beauty. We expect speed cameras to be conspicuous to the motorist and we do not envisage other applications for exemption."

Earlier this year a study found the yellow camera scheme had reduced deaths and serious injuries by 35 per cent in the eight areas where it was first introduced.

Under the new rules, cameras must also be well-signposted and placed only where there have been at least four serious accidents in the last three years.