kin ell - i agree with tunnie 
BA couldn't wait to mothball concorde as it was costing too much, the minute Air France had the accident they pounced 
It is actually the only time in history I can think of whereby we went backwards technologically - concorde was an awesome sight, and it got canned after one incident? do ferrari scrap their f1 car if it ploughs into a barrier? do man united scrap their first team if they lose a game? ridiculous 
Not sure it's quite as clear-cut as that. BA invested a lot into getting Concorde back in the air. Quite and extensive programme of fuel tank modifications and testing. I get the impression it was AF who were dragging their heels at that point.
Rumour has it that Air France came very, very close to losing another Concorde to pilot error shortly after its' return to service. At the time scrutiny showed that the pilots in the original disaster had not handled the emergency entirely "by the book" although their fate was probably sealed anyway.
Air France and Airbus (who inherited type support for Concorde) were desperate to avoid any further embarrassment and, rather than pull out of supersonic passenger services "unilaterally", leaving BA to continue, Air France did a deal whereby Airbus would agree to withdraw the type support for Concorde, grounding BA's fleet as well.
This is just one theory, and I'm not saying BA weren't also looking for a way out, but it seems strange that BA would invest so much in getting Concorde back into the air for just another couple of years.
Don't forget that 9/11 happened in the intervening years too.
Kevin