Talks aimed at averting a strike by thousands of London Underground workers have resumed, with time running out on reaching a deal to head off a damaging walkout.
Almost 20,000 workers are due to strike for 24 hours from Wednesday evening - Budget Day - in a dispute over the new all-night Tube services.
The Rail, Maritime and Transport union (RMT), Aslef, Transport Salaried Staffs Association and Unite are unhappy over pay being offered for the new service, due to start at weekends from mid-September, as well as rosters.
Talks were held at the conciliation service Acas last week without any sign of progress and both sides met again today.
A strike by all four unions would cripple Tube services, hitting the millions who use LU every day as well as tennis fans going to Wimbledon.
Passengers were warned of the impact on Tube services if the strike goes ahead.
A message from Transport for London said: "If this goes ahead, there will be no Tube service from late afternoon on Wednesday 8 July and no Tube service at all on Thursday 9 July.
"All other public transport services and roads would, of course, be much busier than usual.
"We will be issuing detailed travel advice to customers as soon as we can."