British Airways and Virgin Atlantic, two of Europe’s leading transatlantic airlines, joined forces on Monday in a concerted last-ditch effort to try to block the proposed treaty to liberalise aviation services between the European Union and the US.

Martin Broughton, BA chairman, said the deal – provisionally agreed by US and European Commission negotiators last Friday – was “a con trick” and was “likely to be a dead end” that would “put back the prospect of a real breakthrough for many years”.