"Spencer":
I plan to travel from London to Paris on a Sunday in September. I will
arrive in London, ex Oxford, about 11am and see there are Eurostar trains
at 12.02, 12.29 and 13.00. I wonder if is necessary to book in advance or
just get to St Pancras as quickly as possible and buy a ticket then? Are
there any cost advantages either way?
Any comments will be appreciated.

I haven't used Eurostar since they moved to St. Pancras, but they used to
require you to check in half an hour ahead of train time. So you'll need
to allow for that when reserving.

Ian F.:
I would never just turn up at a station to get any train without having made
a reservation, let alone for an international service. What on earth would
the benefits be?

Well, duh! On earth, you get on the first train available. And on
services that don't require reservations, you get to pick your seat.
I would never reserve in advance unless there was a good reason to do so.

In any event, the cheapest tickets are always the ones paid for in advance.

Sad but true. And that *is* a good reason to do so.
--
Mark Brader, Toronto "Don't anthropomorphize evolution:
It hates that." --John Freiler