Plans for a £1.5bn terminal at Heathrow East have been thrown into disarray by a breakdown in relations between main contractors Ferrovial and Laing O´Rourke

A source close to the BAA project, which is known internally as Terminal 2a, said it was “virtually impossible” for the terminal to be finished before 2013, its revised completion date.

Foster + Partners and Ferrovial’s chosen architect Vidal Arquitectos are working in Spain to co-ordinate the design, but it is understood progress has stalled because of the fraught relationship between the two contractors.

The source said: “It’s not been easy. There’s little communication going on between Laing O’Rourke and Ferrovial, and it has slowed down the project.”

As Ferrovial is the owner of BAA, the airport operator is said to be reluctant to intercede between the two.

Another source said the contractors were arguing about the best way to build the design. “The problem Laing O’Rourke has is that when it doesn’t do what Ferrovial wants, then Ferrovial pulls rank.”

When Laing O’Rourke doesn’t do what Ferrovial wants, Ferrovial pulls rank.

Source close to the project

Heathrow East was originally intended to be complete for the London Olympics. BAA said earlier this year it would miss that target, but that the terminal would still be finished in 2012.

It is understood that a midfield pier, known as T2c, designed by Grimshaw and being built by Balfour Beatty, could be partially opened in time for the Olympics.

A BAA spokesperson said: “All contractors involved in the project are fully committed to working together to deliver the programme.”

Laing O’Rourke said: “The relationship is working well and we are fully committed to the construction of the Heathrow East terminal.”