Worried police chiefs today said they are to offer exercise plans to applicants who are so unfit they are failing basic entrance tests.

Senior officers are desperate to get more police on Bradford's streets to try to tackle rocketing crime.

But despite having the cash to take on 55 new police officers a month in the county, in some cases almost half the posts are not being filled - with many candidates just not fit enough to make the grade.

The exercise plan move follows revelations that crime has soared by more than 17 per in Bradford, the largest rise anywhere in the county. One of the district's police authority members said it would take up to 3,000 new officers to reverse the rising trend in crime.

Chris Turton, chairman of West Yorkshire Police Federation - which represents rank-and-file officers - said the situation could leave a third of all new constable posts empty. The force has set aside cash for 1,000 rookies over three years.

And with a high number of experienced officers currently retiring, it leaves the worrying prospect of an actual cut in overall police numbers.

Assistant Chief Constable John Sampson, head of personnel, said: "The fitness test is a major hurdle for many candidates who, because of the short lead-in times now from application to assessment, have not prepared themselves sufficiently for the physical rigours of that test.

He added: "We hope to be able to overcome this in the future by offering to candidates training regimes that they might undertake which should bring them better prepared to the assessment."

He said although the force aimed to bring in 440 new recruits this year, the figures was likely to be 390 - and 21 of these serving officers drafted in from other areas.

Mr Turton added: "At the end of last year we thought this situation might have been a blip but it has continued."

He said that although the budget allowed for 55 new recruits every five weeks, the actual take-on rate was sometimes just half this.

He said: "The most recent intake was just 27 and it is a concern that we are not hitting the target.

"It is crazy because the money is there."

He said: "There have been a lot of people failing on the physical aspect of the process. It is enough to be one of the major concerns."

The test, which includes a series of shuttle runs and gym tests such as press-ups, is designed to "identify a reasonable standard of fitness deemed necessary for today's practical policing".

"People know what is expected of them and they have time to get up to scratch but it is not happening in some cases," said PC Turton.

He said: "We want people who have intelligence, honesty, integrity and who are physically fit. We had a lot of recruitment activity in the 1970s which means we are about to see a lot of retirements. It means we need to recruit a lot of officers just to stand still.

"With the current recruitment situation, who says we are going to remain in plus figures? We may end up having fewer."

Neil Taggart, chairman of the West Yorkshire Police Authority, said: "I am certainly aware that the general level of fitness for younger people is lower than it was 50 or 60 years ago."

If all the new recruits' positions were filled, the force would have around 5,090 members by the end of 2003. This still falls below 1997 levels which topped 5,200.