According the the union, Unite, London Underground faces the prospect of a complete shut down this Bank Holiday weekend as workers, who control the power to run the trains, prepare to strike.
Unite regional officer Hugh Roberts said:
"There is a real possibility that the underground could close down over the bank holiday weekend. Unite is working very hard to achieve a fair settlement for our members - and to avoid the industrial action. The ball is very much in the management's court."
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Before the final declaration on Friday, the Conservative candidate looked set to lose the City Hall race to Labour's Sadiq Khan.
The Tooting MP has been the frontrunner in the counting process ahead of Tory challenger Zac Goldsmith.
It's not just London where elections have been taking place today. There were council elections taking place across the home counties.