National Rail Conditions of Carriage
The National Rail Conditions of Carriage clearly state that you may use more than one ticket to complete the train journey provided that "the train you are in calls at a station where you change from one ticket to another" and this means that split ticketing is allowed and legal. The following extract from section 19 of the National Rail Conditions of Carriage could not be any clearer:-
19. Using a combination of tickets
You may use two or more tickets for one journey as long as together they cover the entire journey and one of the following applies:
(a) they are both Zonal Tickets unless special conditions prohibit their use in this way. The Ticket Seller will, if you ask, advise you whether you can use a Zonal Ticket in combination with another ticket.
(b) the train you are in calls at a station where you change from one ticket to another;
(c) one of the tickets is a Season Ticket (which for this purpose does not include Season Tickets or travel passes issued on behalf of a passenger transport executive or local authority) or a leisure travel pass, and the other ticket(s) is/ are not.
When you buy a ticket to travel on the National Rail Network you enter into an agreement with the Train Companies (TOCs) whose trains you have the right to use. That agreement gives you the right to make the journey or journeys between the stations or within the zones shown on the ticket you have bought. These Conditions are also part of that agreement and they apply to all domestic (non-international) journeys by scheduled passenger trains of the Train Companies on the National Rail Network.
It is a condition of the Passenger Licence granted to each Train Company by the Office of Rail Regulation that these Conditions apply to tickets sold for journeys involving its services and those of other Train Companies. You can view a list of the train companies here.
These Conditions set out your rights and any restrictions to those rights. The Train Companies may give you more extensive rights than those set out in these Conditions and, if they do so, these may be found in each Train Company's Passenger's Charter or other publications. Details of where you can find this information will be available when you buy your ticket. The Train Companies may not give you less extensive rights, except in the case of some types of reduced and discounted fare tickets where the relevant condition(s) specifically allow them to do so. These Conditions set out the minimum level of rights you are entitled to expect.
A Train Company's ticket sales staff will give advice about tickets, and any restrictions concerning their use, on an impartial basis unless the point of sale is dedicated to the sale of one Train Company's tickets.
You can obtain further information by viewing the National Rail Terms & Conditions of Carriage © Copyright Rail Settlement Plan Limited. Issue May 2012 that you may download here.