It is understood that the Ministry of Defence entered into negotiations with Boeing in the summer in order to secure better value for money for the E-7 Wedgetail jets programme.

One option under consideration is to reduce the contract with Boeing fromfive to three E-7 Wedgetails, in a move that is anticipated would save hundreds of millions of pounds over the next decade.

In March last year the MoD signed a fixed-price contract with Boeing for five E-7's in a £2bn plus-deal.

At the time of the announcement rival defence companies were furious that the contract was not opened to competition.

Douglas Barrie, a military aerospace expert at defence think-tank IISS, said: “Reducing the number to three looks like simple financial expediency.


“However, it’s really difficult to see how that number would provide the required coverage as five E-7 Wedgetails were seen as the baseline number of aircraft to give that.”

At any time it would mean one aircraft would be in maintenance, another used for training, with a third actually in theatre, meaning that any problems could create gaps in surveillance coverage.

Mr Barrie added: “Three E-7’s would mean coverage is sub-optimal and Russian air activity is only increasing and we are seeing more incursions than in a long-long time.”

Tobias Ellwood,chairman of the Defence Select Committee,stressed the need for five jets.

“It raises questions that this is a cart before the horse by reducing a high star capability that will help protect our F-35s before we know how they will be utilised.”

Defence sources said that while the MoD has asked for the order to be reduced to three Boeing is working on a “solution” that would be an order for four.

In a statementBoeing said: “Wedgetail is the world’s most advanced, capable and reliable command-and-control aircraft. It will provide the RAF with a combat-proven capability that is low risk and unmatched. We don’t comment on commercial matters.”

A MoD spokesman said: “We regularly discuss equipment programmes with our partners, particularly when it comes to making savings and cutting costs, where appropriate. We are not prepared to provide a running commentary on these discussions.”

• Boeing Co