rossma
It is a matter of deep regret that you and your fellow passengers felt the way you did.
It would not suprise me if BA policy changed in the light of the publicity surrounding this event. Not because it was intrinsically unsafe but because we are governed by perception rather than reality, courtesy of sensationalist and inaccurate reporting and publicity common for all world events.
I am sorry to hear that you will be choosing Virgin next time. Where did you find out that they have a different policy, given that despite the qustion being asked twice, nobody from any other airline has stated what their company policy is?
Finally could I correct one common misconception relating to jet transport aircraft? You say that
The plane went along on the rear wheels for ages before we actually took off and we only just made if off the ground before the end of the runway.
Presuming that the engine did not fail until airborne what you experienced was the normal (not just BA but all operators) practice of a reduced thrust takeoff. This is where all factors such as, air temperature, aircraft weight, length of runway, surrounding hills are taken into account and the safe minimum amount of power required is calculated and used.
The reasons are various not least that the engines are put under much less stress than when operating at full thrust and also the combustion chamber temperatures are far lower resulting in longer engine life.
It also means, as you correctly observed, that most of the runway length will be used before becoming airborne.
There are circumstances when a reduced thrust takeoff is not permitted e.g. conditions of windshear.