Train conductors embroiled in a year-long pay row will reject a new offer aimed at ending the dispute, union leaders claimed last night.

The confident prediction came ahead of a ballot of Rail Maritime and Transport Workers at Arriva Trains Northern.

Up to 700 train conductors will vote on a four per cent basic pay offer plus a lump sum of £250 - in a ballot predicted last month by The Northern Echo.

Today marks the first anniversary of the pay dispute which began on January 24 2002 and has seen conductors at the company take 23 days of strike action.

The on-going action is the longest in recent railway history and one of the longest in trade union history.

Last night Stan Herschel, regional organiser with the RMT, said the decision to ballot was to "shut up" train bosses who have repeatedly called for fresh pay offers to be put to the union membership since an original ballot last year.

Mr Herschel said he was pretty confident the membership would reject the latest offer which he called "obscene".

He said: "Arriva has had the chance to sit down and seriously negotiate with us and has failed miserably.

"Therefore the dispute will continue." Passenger groups have grown increasingly exasperated at the failure by both sides to find a breakthrough in the pay row.

Fran Critchley, deputy secretary of the North-East Rail Passengers Committee, said: "We feel very frustrated and at the end of the day it is the passengers who are suffering and the tax payers who are footing the bill for this."

The RPC has called for intervention from the Strategic Rail Authority but its pleas have so far fallen on deaf ears.

A spokesman for the SRA - which heavily subsidises Arriva services - said they did not have a role in pay negotiations and it was up to Arriva to come to a settlement which it could manage within its existing budget.

The dispute began when Arriva gave a 18 per cent pay rise to its drivers in a bid to tackle a driver shortage.

A number of different pay offers to conductors have since been rejected.

Ray Price, managing director of Arriva Trains Northern, said the company's conductors had their first opportunity in more than 12 months to have their say and urged them to vote in favour of the new pay offer.

*One of the North-East's longest industrial disputes involved staff at Darlington's Magnet factory and ran for 19 months until sacked workers received a pay settlement.