An FA spokesman said: "Multiplex are the expert contractors working to a fixed price contract. Therefore we have to be guided by their experienced advice that Wembley will be handed over to The FA by the end of March 2006 and be open for The FA Cup Final.

"However it would be naive of any organisation involved in such a huge building project not to have alternative plans in place - should any unforeseen problems occur.

"Therefore, The FA is currently in negotiation with an additional venue - purely as back up. The public would expect that when we are responsible for hosting the most prestigious domestic cup competition in world football.

"We would also like to make it clear that we would only consider an fallback venue which has a proven track record of hosting FA matches."