RAF Jets over-fly SE London

Hi,

RAF Jets over-fly SE London

Anybody know whether there is an exercise going on, either –

1. Training for the Olympics (air cover ?)
2. Has there been a terrorist threat over / in London today ?

My place has just been “buzzed” by 3 Tornadoes, orbiting over the M25 / A20 junction at Swanley – Orpington at 9pm on Saturday 21-01-2012. They went round at least twice before heading off towards the Greenwich direction (NW) – up the Thames.

Any clues ?

Cheers, PBY