Sorry but disaggre with A fully ladend 747 has 216847 or just over 200 tons of fuel. If The wind is coming from the east they will take of from Heathrow directly over London.
Planes taking off in an easterly direction from Heathrow have to turn before they get there, flights are not permitted to overfly the city.
If on take off the plane was hijacked in a 9/11 style there is NO way any RAF fighter plane could take off and intercept before the 747 is over any target over London. Only the primister can give that order. Be a brave man to give that with out thinking .
Firstly, an aircraft could only be hijacked in a '9/11' style with the cooperation of the flight deck crew - I was involved in fitting 'anti-terrorist-doors' on some aircraft, and you can't just 'break them down' they need to be opened from the cockpit, they're bullet proof too.
Secondly, the RAF don't operate a 'scramble' system in these kind of situation - the fighters are already airborne flying what's known as CAP, (Combat Air Patrol), for 4-5 hour stints with a reserve flight on the ground, and can get to most places very quickly.
Thirdly, it's usual for the decision to be 'readied awaiting final clearance' which means the PM, (or his 'authorised deputy'), can be contacted for final clearance while the fighters are en-route to an intercept.
As for Missiles what a joke. Shoot down a Airbus A380 there will be massive loss of life on the ground.
In the west we critiase groups that hide there wepons in amongst cilvians yet we are thinking about doing it.
Having seen the mess a 747 makes, your statement should say 'there
could be massive loss of life on the ground', but when you consider there could be 70,000 people in the stadium, and you might get 300-500 passengers and a couple of hundred ground casualties , (say 500-700 in total), that's a factor of 100 lives saved by shooting a 747 or 380 down - so not a difficult decision really.
There's a big difference between placing defensive weapons in or near a city, as opposed to basing offensive weapons, (e.g. your artillery) in a similar location.
Mark.