Up to 30,000 motorcyclists will have to arrange alternative cover after Allianz Cornhill said it will quit the £100 million market from March, writes Mike Cooper.

Most policyholders will be told by letter of an opportunity to transfer to NIG, which has agreed to renew cover on a case-by-case basis. Customers taking up NIG's offer will not need to complete a proposal form.

Gareth Jones, personal lines and marketing executive at Allianz Cornhill, said brokers have been advised of the move.

"The early indications from our broker partners suggests that they understand our position and we will be working with them to ensure that this decision has the minimum impact on their businesses."

Special arrangements will be put in place for customers of up to eight brokers who conduct the bulk of their business with Allianz Cornhill which has ten per cent of the market.

A spokeswoman for the insurer said it was possible that premiums could rise following the handover to NIG, which takes effect on March 1.

The company has blamed disappointing growth in the motorcycle insurance market for the "tough" decision to quit. It intends to concentrate on its more established household and motor markets instead.