Millions of passengers due to fly from Heathrow this summer face widespread confusion this summer as fury greeted BA delays in moving its long haul services into Terminal 5.

The airline moved was scheduled to move the second wave of aircraft to T5 on April 30.

But the widespread chaos following the terminal opening has forced a delay until June at least.

The decision has an enormous knock-on effect for 54 other airlines due to move terminals at Heathrow following BA's consolidation at T5 - they have spent years planning their moves and had already begun informing passengers of the planned changes.

"This is now going to have a huge ripple effect - it's just a shambles," said Phil Shepherd, a spokesman for Bmi, Britain's second biggest airline. "We already have a campaign under way to tell passengers what's happening - now we don't know where we stand."

Nigel Turner, bmi chief executive officer, added: “It is an absolutely outrageous announcement by BAA and done with no thought, consideration or consultation of any other airline other than BA. The sequence of moves affects over 50 airlines, including bmi, at Heathrow.

"The programme and timescale of changes was agreed in joint consultation with all airlines that are now geared up to undertake the moves as agreed. It was a consultation process that took some considerable time to achieve.

“BA through their mismanagement of the move to Terminal 5 will materially disadvantage all other airlines at Heathrow whilst BAA, through their perverse regulatory system, will actually benefit financially. The UK is once again a laughing stock."

Bmi is part of the Star Alliance of airlines. While Bmi always planned to remain in Terminal 1, its alliance partners - including Air New Zealand and United Airlines - were preparing to leave Terminal 3 and join Bmi in a move designed to make passenger connections far easier.

The airlines have already incurred costs likely to run into the millions in engaging contractors, planners and consultants.

But all airlines affected now have to contact passengers again to correct their travel information - and wait for news of a confirmed moving date. The development is bound to cause confusion for the 16m passengers due to fly from Heathrow in the next three months.

It will also add to travel times for many passengers connecting through Heathrow - BA's summer schedules assumed connections through T5: now many domestic passengers will have to swtich terminals to catch their onward long-haul flights.

Another airline alliance to be hopelessly stranded is Skyteam. Its members, including KLM, Air France and Northwest, were all due to be merged into T4 after BA's departure.

A spokeswoman said: "SkyTeam is disappointed by BA and BAA's decision to delay BA's long haul services from T4 at Heathrow to T5. SkyTeam is currently evaluating the impact of this decision on its transition plans to T4 and working to mitigate the impact on its customers."

A spokesman for Virgin described events at Heathrow since the opening of T5 of March 27 as "a complete cock-up." Virgin consolidated its operations at T3 recently and is not affected by today's announcement.

The BA/BAA statement this morning said: "BAA regrets this postponement, and we recognize the impact it has on other airlines, but we believe it is a wise precaution to ensure that passengers can have the maximum confidence once the move does take place.

“We will be working very closely with BA in the intervening period to ensure that result, as well as working with the other airlines to mitigate as much as possible the knock-on effects.”

“BAA fully recognizes that the inauguration of Terminal Five has not been as smooth as we and BA would have wished. In the last few days passengers have seen significant improvement and our goal is to complete that process as soon as possible before continuing the next phase of transforming the rest of the airport.”

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