A TRIAL to reduce the capacity of the M25 slip road in Hunton Bridge will cost £145,000, it has been revealed.

The Highways Agency will remove one lane from the Junction 19 entry on February 26 for one month, to persuade drivers to stop using Watford and surrounding villages as a rat-run.

They believe cars leaving the motorway cause congestion when they rejoin at Junction 19 and if successful, the trial may be made permanent at a further cost of £45,000.

A Highways Agency survey in April 1999 found 27 per cent of cars and vans, and 34 per cent of HGVs, were rat-running between Junctions 21 (M1) and 21a (A405) to Junction 19. It also discovered three per cent of cars and vans, and ten per cent of HGVs, were skipping the motorway between Junction 20 (Kings Langley) and Junction 19.

During the trial, cones used to split the spur road will cost £50,000. CCTV for one week before and its duration will cost £95,000.

Martin Deller, from the Highways Agency, said: "This trial will give us the concrete data needed to inform decisions so we do not have to rely on computer modelling."

County Councillor Stephen Giles-Medhurst said: "The Highways Agency has not even bothered to tell local councillors they want to waste this huge sum of money. For years residents and myself campaigned for noise reduction measures along the M1 between junctions five and six to protect the Meriden and Lemonfield area. "

Keith Williams, leader of Abbots Langley Parish Council, said: "This will compound the problem they are trying to resolve; more traffic will be forced to find alternative rat-runs."