Boarding for my Eurostar is delayed and I'll miss my SNCF connection, what should I do?

Yes, there is! For most people, head to the Eurostar information desk on the right of the departures area. For those with Carte Blanche or Business Premier, head to the information desk downstairs in the lounge by the entrance.

Let the staff there know which train you are on that was delayed, and that you have onward connections. Give them your onward train tickets. They will hunt around in the draws for the magic CIV stamp, then stamp your onward tickets. They should also write a note about the delay on the back for the SNCF staff.

On arrival in Paris, for trains with compulsory reservations you should see ticket off staff in France, or otherwise staff on the French train before boarding to get new seats. For non-reservation trains, your tickets should now be fine.

Your stamped tickets should be something like these:

This depends on how many tickets you have.

• If you have a ticket for the Eurostar and a separate ticket for the onward connection, you are on your own. You can try to ask nicely and you may get lucky, but you typically won’t.

• If you have a single ticket for the entire connection (i.e. you booked the entire trip in one go), you are entitled to transportation to your ticket’s final destination as long as you reached your first leg on time.

  Go to the information desk of your departing station, the conductor on the train or the information desk of your arriving station — whichever is most convenient — and mention the story. All three have a magic stamp (or at least some of the powers of a magic stamp) to make your ticket valid for later connections. Personally, I would make my way to a desk like that as soon as I realise that there is a delay — in the question’s case this would be right in St. Pancras. Especially if either of the trains includes compulsory reservation or is global priced (Thalys, Eurostar, TGV being the most important ones).

  Even if you don’t do this until Paris (or wherever you get off), they still have the magic powers of a computer database to check whether the train was really late (i.e. your story is plausible).

  If, due to exceptional delays or a long journey, you cannot reach your final destination by train on the same day, you are typically entitled to either a taxi voucher or a hotel voucher (at the discreetion of the train companies).