You beat me to it helen. No 4 engined aircraft is certified to survive a loss of thrust on 2 engines during take off.
Some thread creep I'm afraid but SSG is annoying me somewhat by stating things as fact when they are not so clear cut.
Re the Concorde crash my understanding is that there is evidence the aircraft was about 1 tonne over structural MTOW (due to loading extra taxi fuel and some bags that the crew did not know about). Illegal but not an outrageous risk in itself and certainly not grossly overweight. Plus the crew were unaware that some of that weight was on board. What changed was the wind from calm to 8 tail which put them about 6 tonnes over RTOW. The crew did not pick up on this for some reason. The loading of fuel and bags may also have been suspect and may have put the C of G too far aft.
There is also evidence that a spacer was not fitted to the gear causing it to lose tracking when the tyre burst and cause the aircraft to veer and possably hit a runway light which may have contributed to the failure of the second engine.
The crew were forced to rotate well below VR and never made it to V2 due to the loss of 2 engines, the tailwind and the poor tracking caused by the missing spacer.
Even with the weight if they'd just lost the one engine they would probably have got away with it, sadly they lost 2 and some evidence suggests that was because of the missing spacer causing poor tracking after the tyre burst restricting accelaration and causing them to hit a runway light that may have caused/contributed to the second engine failing. If they had been at the correct weight for the conditions that failure on the second engine would still have downed them so my view would be the spacer (or whatever else led to the loss of the second engine) was the more critical secondary factor not the weight. The main factor remains that damned metal strip that caused the original tyre burst.
So SSG carefull when you say it was down to the aircraft being overweight as if that is a fact especially as much of the above is speculation to a greater or lesser extent.