By Lucy Wilkins
BBC News Online
UK officials feared the French would blame "British incompetence and defeatism" if Concorde failed to sell, secret documents have revealed.
Concorde retired in October 2003
Documents released on Thursday by the National Archives under the 30 years rule, show that officials grew increasingly worried in 1973.
The Department of Trade and Industry feared both US reluctance to buy, and a French inquiry into the jet.
The joint Anglo-French project was behind schedule by 1973.
French prime minister Pierre Messmer had appointed Rene Bloch to investigate how the project was proceeding, 11 years after France signed a treaty with Britain to develop the plane.
Admiral Bloch's visit to Britain in 1973 prompted a flurry of top secret communications between officials, the files show.
In one to Prime Minister Edward Heath, an official says of Admiral Bloch:
"He says that Messmer called him in on the grounds that the project is in a mess and that he should take over.
"There are indications that this might not be all the story...and we cannot be sure that an enquiry of this sort will avoid all dangerous ground."
They were worried that the French would blame "British incompetence and defeatism" if no international orders came in.
The consortium was already building planes for planned UK and French use.
But international sales talks, principally with America's TWA and Pan Am airlines, were not going well.
Officials were briefed not to mention anything that could affect French opinion of British involvement and to keep "a careful eye on [Bloch] and on the people he is seeing".
"He is clearly a man who believes in Concorde and does not consider himself called upon to preside over its demise," another memo states.
"At the same time, he is highly critical of the entire management structure, both official and industrial."
The prime minister was briefed by the Department of Trade and Industry that its "concern is to ensure that the continuing slippage in the development and production programme is halted.
"The main reasons are all too clear. A lack of firm orders, and a consequent belief by the workers that their jobs are at risk, causes them to spin out the available work as long as possible," the prime minister was told.
The department warned that it was "necessary for the UK to remain totally uncommitted to any production scheme beyond the first 16 aircraft, if we are to have any possibility of establishing a right under the Treaty to terminate our support for the project, should we later wish to do so".
In the end, the international orders failed to materialise and Concorde had to be practically given to British Airways and Air France.
Both Pan Am and TWA cancelled major orders which were the first major blow to the aircraft.
They were swiftly followed by Qantas, Sabena (Belgium), Lufthansa, Air India and Japan Airlines.
The remaining Concorde fleet used by British Airways and Air France was retired in 2003.