Rail conductors involved in a bitter pay dispute with Arriva Trains Northern are to be balloted on the latest pay offer.

But union leaders have urged their members to reject the deal and continue their year-long campaign which has included 23 strikes so far.

Arriva insist the offer is worth 4% on basic pay and a lump sum of �250.

Bob Crow, general secretary of the National Union of Rail, Maritime and Transport (RMT), said the deal was a "disgrace".

This will be their first opportunity in over 12 months to have their say on the issue Ray Price, managing director Arriva Trains Northern

"It seems that the company is celebrating the anniversary of this bitter dispute by halving what's on offer for the second time.

"This is a disgrace from a company that gave its drivers an 18% increase in the same pay round.

"This is the only dispute I can remember in which the pay offer has gone down every time we've got round the table with the employer.

"The Arriva staff reps threw this latest insult out and the executive is now asking all Arriva conductors to do the same in a referendum."

Ray Price, managing director of Arriva Trains Northern, said: "We welcome the RMT's decision to hold a referendum for its members on our latest offer.

"This will be their first opportunity in over 12 months to have their say on the issue.

"We believe this is a fair offer and we urge our conductors to vote in favour, especially as the RMT has accepted offers at Arriva Trains Northern and other companies which are similar to or less than what we have put forward."