America's largest defence companies have attacked the Senate foreign relations committee for its decision to delay a defence treaty designed to bolster USBritish defence co-operation until the next Congress.

In a letter to the committee chairman, Joe Biden, who is also the Democratic candidate for the vice-presidency, the Aerospace Industries Association (AIA) said failure to approve the treaty this year "would be an unfortunate setback in ongoing efforts to shape an export control regime that will serve America's interests in the 21st century".