British Airways’ protracted dispute with its cabin crew moves towards an end game this weekend after the negotiating teams set a Tuesday deadline to reach agreement or face inevitable strike action.

The Unite union, which has an overwhelming mandate from its cabin crew members for a stoppage, says that it will announce strike dates next week if a breakthrough cannot be achieved by 5pm on Tuesday.

The two sides will continue to meet for talks chaired by Brendan Barber, the TUC general secretary, until then.

Should the negotiations fail, the union must give BA seven days’ notice of a stoppage, so strikes could not begin before March 16. It has already promised not to interrupt the busy Easter school holiday period during the first two weeks of April.

Tony Woodley, the joint head of the union, has told The Times that he would favour a three-day stoppage. However, many cabin crew believe that a strike would have to last for at least a week to make any real impact. A source close to the talks said: "Ten days has never been over the top."

A Unite spokesman said last night: "They are difficult negotiations, certainly. The law imposes some degree of deadlines and we will have been talking for six or seven weeks now and in the end we have to see if we have an agreement or not. If there is no agreement there will be strike dates set."

BA said in a statement: "We have agreed to work towards the objective of completing talks by the end of Tuesday."

The company’s chief executive, Willie Walsh, threw down the gauntlet on Wednesday with a warning that he would be forced to implement deeper cuts if crew strike. He accused the union of dragging its feet in negotiations and of being so divided that it was unable to negotiate a resolution. He insisted that changes he made to cabin crew numbers in November — the immediate cause of the dispute — would not be rescinded. BA has removed one steward from all flights and two from some long-haul services as part of a cost-cutting drive which aims to save £140 million from its annual cabin crew budget.

BA has trained 1,000 staff to fill in for striking cabin crew and will charter 23 aircraft and crew from rival airlines to fly out of Heathrow Airport if stewards do walk out. It has pledged to keep all long-haul flights out of Gatwick and about half of its short-haul flights from that airport running in the event of strike action. None of its 50 daily flights from London City airport would be hit.

A 12-day Christmas strike was outlawed by the High Court, but a second ballot last week showed that 81 per cent of cabin crew favoured a stoppage on a turnout of 79 per cent.