Talks resumed on Wednesday between British Airways officials and trade unionists, in an attempt to prevent further strike action by ground staff.

There is hope for an early end to the dispute, after "positive" discussions were held on Tuesday.

The row centres on a new electronic 'clocking-on' system at Heathrow airport, which unions claim could lead to staff being forced to work extra shifts at short notice.

BA has denied the allegations, arguing that they are simply replacing an inefficient paper clocking-on system.

A 24-hour wildcat strike was held earlier this month, forcing the cancellations of more than 500 flights.

Union sources are reported to have claimed that the controversial swipecard system will now only be imposed on a voluntary basis, and that a three per cent pay rise for staff would not be conditional upon its introduction.

Later this week, the airline will publish an indication of how much recent industrial action has cost.

This is in addition to figures being published on Thursday, which are expected to show losses of between £60 million and £70 million during the last quarter.

These will include the impact of the Sars virus and military action in Iraq, but will not reflect the effect of the recent dispute.

Liberal Democrats warned that a continued dispute could result in job losses.

"The airline industry is one of the most competitive markets in the world," said transport spokesman Tom Brake.

"With many airlines already struggling to survive, it is vital that as the peak holiday period approaches British Airways and the unions resolve this dispute as soon as possible.

"Prolonging this clocking-in dispute will cause not only misery amongst holidaymakers, but also amongst the families of the workers who could find themselves clocking off permanently."