How is it that the UK and US don't pay ransoms and other countaries do?

In the Premier League of ransom payers not surprisingly France takes the top spot followed by a collections of other states like Italy, Spain, Switzerland, Belgium, Austral and Germany and a few other 'rag tag an bob tails'. The only two that don't are the UK and US - why only them? David Cameron apparently told the other leaders at the Nato Summit in Wales that this was no good enough as they had all signed up last years G8 summit that they would not do so. However they had not stuck to that undertaking. The rationale for not paying is very clear - it only positively 'reinforce the taking of hostages' - its a jolly good little earner at no real cost to the those doing it.