According to Howards Solicitors, the police are investigating alleged irregularities relating to responses they have received from drivers who were originally sent a NIP.

The police appear to be offering an amnesty from prosecution to all who are prepared to admit an offence of perverting the course of justice, a figure that is thought to number more than 600.

Fleet professionals as well as private drivers have been targeted.

The issue arises from a member of The Police Central Ticket Office allegedly accepting illegal monies to bury notices for speeding and other traffic offences over the past three years. The individual has since been removed from the post and prosecuted.

Oliver Gardner, who is managing director and head of motoring law at Howards Solicitors and is currently representing some of those drivers concerned, commented: 'There could be any number of reasons why a notice has not been responded to that does not have any hint of illegal activity.' However, he said that the letter seem to be encouraging drivers to attend police stations around Manchester to be arrested and interviewed under caution for offences of perverting the course of justice. The police then offer to issue a caution rather than instigating court proceedings in return for an admission.

Mr Gardner advised caution over proceeding with such a line of action, saying that it could have serious repercussions in the future. He said: 'Perverting the course of justice is a very serious offence and even a caution for such an offence can have significant implications.

'Professional drivers in particular must not admit guilt if they believe they are innocent in order to get the issue out of the way as the future implications as far as work prospects are concerned may be disastrous.'

All recipients of a NIP have the right to legal advice when being interviewed by the police and in some cases this may be free.  Requesting a lawyer will not delay the process or be an admission of any guilty whatsoever.