As long-distance train operators prepare to run near-normal rail services from Monday, passengers are warned they should book ahead or risk being turned away.

LNER, the publicly owned operator linking London King’s Cross with Yorkshire, northeast England and Scotland, will insist on reservations from 11am on Monday 18 May.

The train firm says: “Anyone travelling with LNER will require a seat reservation before boarding the train.”

The measure is designed to limit the number of passengers on each train in order to maintain social distancing of two metres.

The reservation will not initially be for a specific seat. Instead, it will effectively be a “control ticket” to limit the numbers on board each train to one-fifth of the number of seats.

This is a reversal of the policy that prevailed before the coronavirus outbreak. Previously anyone could buy a “walk-up” ticket for any train, even if it was fully booked, on the understanding that they might have to stand for the whole journey.

Those with an advance ticket can just board and choose their own seats, while travellers with season or “walk-up” tickets will need to obtain a reservation for their chosen train.

From 13 June, socially distanced seating will be allocated by the LNER reservations system, and specific seat assignments will be given.

The number of passengers allowed, 20 per cent, is twice as many as the estimate by the transport secretary. Grant Shapps warned social distancing measures on board trains reduced capacity by 90 per cent.

At present the only people who can use trains are those who cannot work from home and must travel to work, and those who must make an essential journey.

Avanti West Coast, which runs from London Euston to the West Midlands, northwest England, north Wales and southern Scotland, is introducing a similar system.

Phil Whittingham, managing director of Avanti West Coast, said: “We’re appealing to our valued customers to help us and other passengers by only travelling with a reservation.

“If everyone does this, we’ll be able to keep social distancing in place on board, both for our customers and our people.

“If customers do turn up without a reservation, we’ll do our best to help but we can’t guarantee they’ll be able to take the train they want.”

Mark Smith, the former British Rail manager who runs the Seat61.com website, said: “It’s arguably the simplest way to limit trains to 20 or 25 per cent capacity and ensure social distancing in these unprecedented times.

“Indeed, even some French regional trains have recently introduced seat reservations for this reason. Previously no regional train ever offered seat reservations even if you wanted one.

“Just as long as things return to normal eventually – we Brits value our ability to travel flexibly and spontaneously, without having to reserve a specific train for every journey in advance.”

On-board facilities are limited. GWR, which serves Wales and the West of England from London Paddington, says: “There are no refreshments being served on board any of our train services.”

LNER has banned alcohol from all trains for the past few weeks. A spokesperson said: “To enable us to focus on assisting those for whom travel is essential and to support social distancing, customers are not currently permitted to bring alcoholic drinks onto our train services.”

Read More