Traffic police are getting tougher on motorcyclists who break the road rules, in the wake of a rise in biker deaths.

Twenty motorcyclists have died on North Yorkshire roads in the first eight months of this year.

It compares with 23 deaths for the whole of last year and 13 in 2001.

And though deaths were down from 18 to 14 in West Yorkshire last year, a spokesman for West Yorkshire Casualty Reduction Partnership said there had been a steady increase in the number of motorcycle casualties since 1997. It had risen from 539 in that year to 822 in 2002.

"Sadly, motorcyclists remain the only road-user group in West Yorkshire whose casualty figures in road crashes continue to rise," he said.

In North Yorkshire police are to take a harder line against speeders, racers and white liners. And bikers doing wheelie show-offs and displaying other anti-social behaviour will be targeted.

The crackdown coincides with the launch of a new motorcycle safety scheme called Handle It Or Lose It.

The county's seven Community Safety Partnerships are involved in a leaflet advertising campaign aimed at riders of sports bikes. It is part of the Bike Safe campaign which has been run by the county since 1997 and encourages riders to make an effort to learn to handle their bikes properly.

Officers are toughening up the campaign and have pledged to take more enforcement action against law-breaking bikers.

A North Yorkshire police spokesman said: "The emphasis has shifted more towards enforcement and a harder line, including those who fit ear-splitting racing exhausts to their machines."

At the same time, the force is reinforcing the message to other road users to be aware of vulnerable motorcyclists.

"By no means are all motorcycle deaths the fault of the rider involved."

In North Yorkshire between January 1994 and August 9 this year, 155 motorcyclists and their pillion passengers died on the county's roads.