British system has 1 Trillion = 1,000,000,000,000,000,000 American system has 1 Trillion = 1,000,000,000,000 This is the reason British are richer and stronger than Americans and British pound is richer than US Dollar.
The UK has moved towards the US representation of 12 zeros for trillions and 9 zeros for billions. I would argue that the US is in a better position for long term recovery than the UK at this moment.
UK's external debt to GDP ratio is 388% US's external debt to GDP ratio is 100% http://www.usdebtclock.org/world-debt-clock.html