Thanks a lot for this answer.
try to get hold of Ken Owen's "Concorde New Shape in the Sky" ISBN 0 7106 0268 5. It is an excellent account of the genesis and development of the machine that drove my life for 25 years.
Added to my list, just below the "The Wind Beneath my Wings" by John Hutchinson.
we are talking of the UK and France of the 1950s. No way that either of those two proud countries was going to let the other have the lion's share of the kudos and fun of developing and flying the world's first supersonic airliner.
That makes me bounce back to the last question of my previous post. Just regarding the 2 prototypes, since they were built simultanuously, I assume that, from a technical point of view, they were identical. And I assume also that the reason to build 2 identical prototypes was mainly to respect this principle of fair and equal share between the 2 countries; am I right?