Small business owners in London have been warned that they could face travel disruption at Christmas as a tube union has voted to bring in a ban on overtime working.

Engineering electrical workers on the underground could take the action in a row over pay. Members of the union Unite have rejected a ‘full and final' two-year pay deal by London Underground and have voted against a full strike action, preferring to action an overtime ban instead.

"It would have an effect on services because our members are responsible for getting the trains ready for service, as well as maintenance and safety," said John Morgan-Evans of Unite.

The underground network has been hit by a series of strikes this year, including a 48-hour tube strike that was estimated to have cost the London economy £100m.