British police chiefs said Thursday they will not go ahead with a planned 93-page guide telling officers how to ride their bikes, after its simplistic advice was mocked and its expense criticised.

The Police Cycle Training Doctrine included advice such as not to tackle suspected criminals while still "engaged with the cycle" - on the bike - and has a diagram showing "deployment into a junction" - turning left or right.

The draft document also explained how to balance so as not to fall off, how to brake, and urges officers to wear padded shorts for "in-saddle comfort," and remember to "rear-scan" - look over their shoulders.

Undercover police were advised that they may have to cycle without a protective helmet to avoid being found out.

But, underlining the importance of sometimes-criticised health and safety laws, it warned: "This lack of protection must be noted and a full risk assessment of the required role... be undertaken."

Reacting to the revelations in the Sun newspaper, the Association of Chief Police Officers (ACPO) said it would not be publishing the guide.

"This work was neither requested nor drawn up by ACPO and we do not endorse it," said a spokesman. "It was put forward by a group of well-meaning police officers with an interest in this area.

"ACPO will not be taking it forward," he added.

Reacting before ACPO shelved the plans, critics said it was a waste of money.

"I am sure it is of great value... but I think you can do this kind of thing much, much more cheaply," said London mayor Boris Johnson, a keen cyclist who has sought to boost bike use since taking office last year.

"This is an absurd waste of police time and thousands of pounds of taxpayers' money," added Mark Wallace, head of the Taxpayers' Alliance lobby group which campaigns against misuse of public money.

But Dave Holladay of the National Cycling Organisation rejected the charge that the guide was too long, and defended its contents.

"I would quite expect a manual on police cycling to tell police officers how to turn corners correctly," he said, adding: "The advice of getting off the bike is actually included in most police bike training."

"Police cyclists have to be exemplars," he told the BBC.