The Advance Fares FAQs posted by Hairy Handed Fool suggest that when buying domestic Eurostar connections CIV is not actually necessary to ensure that passengers are put on the next trains if delayed. So does it actually matter in any way any more whether or not you buy a CIV ticket? Do staff at Eurostar and domestic TOCs respond better to CIV tickets than to others because they are not aware of the Advance Fares FAQs? When I once encountered serious Eurostar disruption which made me miss a domestic connection I had a CIV ticket and the TOCs were very accommodating (I have never had the experience the other way). My ticket was in fact inspected very carefully on this occasion - I wonder what the result would have been if I had not held a CIV ticket?
Q22. Can a passenger travel on any other service than the one on which they are reserved, without changing the booking?
A. the following principles apply.
1) Start of the Journey. It is the passenger responsibility to turn up at the start of the journey in time for the departure of the first train. If they miss it due to parking problems, taxis not turning up, etc, they must buy a new ticket,
2) Once the journey has begun. If the passenger is delayed and the train company or it's partners [are] at fault, which should be check by [staff] control office, change to a train of the same company is allowed to get them to their destination with the least delay. This is irrespective of the combination of rail tickets held. Examples are:
Included: are passsengers on valid:
...
Combination of Eurostar tickets into the UK and then either advance tickets from London terminals or "London Intnl CIV" or Lndon Eurostar CIV;