Christmas could be severely disrupted for thousands of rail passengers if South West Trains (SWT) staff decide to strike.

Members of the National Rail, Maritime and Transport Workers Union (RMT) could walk out in a dispute over pay and disciplinary procedures.

Having already rejected offers of a 3.8% pay increase, members are now voting on whether to throw out a proposed 4% rise. Pointing out that train drivers are in line for a 7% pay hike, the union is claiming the deal on the table is unfair. The ballot closes on December 17th and if RMT members reject SWT's offer the union's council of executives will decide whether to take action.

Acting general secretary, Vernon Hince, said: "Non-driver members are sick to the hilt of being treated like second-class employees."

But Andrew Haines, SWT managing director, said: "We feel these are generous offers, especially set against a backdrop of widespread job losses in other industries.

"It is unfair to cause Christmas chaos on our network. Our passengers have already suffered enough with strikes."

The union is also concerned about disciplinary procedures facing two RMT members. The charges against both are safety related and their cases are currently being heard at employment tribunals.

Mr Hince said: "A number of our members have been subjected to ridiculous disciplinary charges on spurious grounds. The company appears hell-bent on breaking the established procedures to which this union is signatory."

But SWT insist proper disciplinary procedures have been followed. "In each case the sanctions received are entirely consistent with those received by individuals who are not RMT representatives," said Mr Haines.

"We have offered to demonstrate this to the RMT, but they have insisted on taking the issue to the ballot box.

"We want to break the constant cycle of ballot, strike, ballot, strike, and we urge the union to come to the arbitration table to thrash these issues out."

* SWT has announced new fares from January, with commuters paying less. The price of most season tickets and standard day singles and returns will fall by 1.4%. Off-peak fares will rise by just under 1%.