Like most three-quels,
World War Three PFTBTFTBTTPPFFFFFFFF! was a serious downgrade from the previous entries. World War Three was a conflict fought in a single room by three people against a single family. It ended with the begin of the 3 month long Golden Age of Britain.
The Doctor and some losers are under siege in Downing Street, where they discover, much to their shock, that Bush did 9/11. Luckily, the Doctor is able to order a stealth missile launch that, coupled with a controlled demolition and a holographic plane, allows him and his buddies to escape. At the last moment, Blon Slitheen also escapes (somehow?), resulting in the British government being completely decapitated and a cryptofascist from Flydale North taking over the nation.
So, to recap:
- Faked crash into large building
- Trumped up fake war over "mass weapons of destruction"
- Facist regime installed