[mathw]

Does depend where you are though. If you're in London or Paris or in easy reach of the Eurostar stations by train, then Eurostar is amazing.

If you're in the north of England, it'll take you longer to get to London than it will to get from London to Paris afterwards. At that point flying starts to look a lot more attractive.

[lorenzhs]

But then we're not comparing Paris–London travel times any more. You'd probably be faster off flying from Manchester.