The Dartford River Crossing could be paralysed if staff go on strike over a pay dispute, it was feared today.

Toll-booth operators and other workers who operate the twin tunnels and the Queen Elizabeth II Bridge are to be balloted over industrial action.

And if they decide on a walk-out, it would bring chaos to a key section of the M25 and have a serious knock-on effect on major roads throughout south Essex.

An overwhelming majority of Unison members, employed by Dartford River Crossing Ltd, has requested a ballot on options for industrial action.

The move comes after talks broke down between the union - representing 100 uniformed and white-collar staff - and the company over pay.

The union wants a 4.5 per cent pay rise, while the company has offered 3.5 per cent.

The union says it wants more to compensate for the fact that its staff could be made redundant in five years' time.

In 2003, toll booth operators could lose their jobs when the money spent on building the QEII bridge is finally recouped.

Government legislation would mean that tolls for the bridge and its matching twin tunnels would then be abolished, decimating the number of staff needed on the crossing.

Paul Godwin, senior regional officer of Unison, said: "There is a lot of anger towards the company over the pay offer and its general attitude towards the employees.

"The company appears to have a total lack of understanding of the feelings of our members about the uncertainty of their future when the current toll arrangements finish.

"This fact, in conjunction with the poor pay offer of 3.5 per cent from a company making large financial surpluses, has contributed to the members' feelings.

"Any or all of the proposed action, if confirmed in the ballot, will cause significant disruption at the crossing, but it was felt that this was the only way of getting through to the employers."

Alan Hobson, operations manager at the crossing, said: "There's not really a lot that I can say at this stage.

"We are still in negotiations and all we would like to add is that if there was to be any action taken, we will do our best to ensure that it does not affect people using the crossing."

The timetable for the ballot has not yet been agreed, but union officials say it should take place early in the new year.

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