Reeve says that current initiatives – DIY tickets on a small number of services on specific routes by just three rail companies through thetrainline – work because rail firms can ensure that ticket inspectors are briefed on what to expect and are actually present on board to ensure everyone has a ticket, whether real or virtual.

“The problems arise when someone needs to travel from, say, Manchester down to Euston, then cross London on the Tube and then take Southeastern Trains to their final destination,” says Reeve. “Who is going to check that ticket on the Tube or on a commuter service?”

ATOC, the umbrella organisation representing Britain’s rail firms, has recently started looking into technology that will allow people to download e-tickets to their mobiles.

George Muir, ATOC’s director general, says: “Passengers want more convenient ways to buy train tickets. Technology can go a long way to remove the need for passengers to queue at ticket offices or wait for tickets to arrive in the post. We are looking to exploit the technology as rapidly and effectively as possible.”