Engineering work is set to scupper the journey plans for hundreds of thousands of August travellers.
The train operator, which runs express trains on the line linking London with the West Midlands, northwest England, North Wales and southern Scotland, has already sharply reduced its schedule due to staff shortages.
The normal links from London Euston to Birmingham and Manchester, with trains every 20 minutes, have been cut by two-thirds to just one per hour because of crewing issues.
Until 30 August, the train operator says: “Avanti West Coast timetables are amended to manage staff shortages and ensure a reliable service, so you can travel with confidence.
“We strongly recommend you book a place on your preferred service and only travel on that train.”
But bank holiday rail passengers will have to scramble for tickets when they finally go on sale.
Network Rail says: “An amended timetable will be in place to/from London Euston all weekend, with platforms 12-16 out of use.”
The closure is due to preparatory works at the hub for the new HS2 line at its terminus in the capital.
A Network Rail spokesperson said: “Passengers should be able to book their trains in advance and we accept timetables being published at short notice isn’t good enough.
“As the country emerges from the Covid pandemic, there are still big challenges facing the railway which we are working as an industry to address so we can give passengers the service they deserve.”
The latest figures for transport use, published today by the Department for Transport (DfT), show car journeys running at 5 per cent above pre-pandemic levels over the last two weekends.
Rail use, meanwhile, is at only 55 per cent of 2019 passenger numbers.
Since the coronavirus pandemic began, passenger numbers have generally been at least as high at weekends as during the week.
But big rail projects are still locked into the idea that weekends – in particular, bank holidays – are quieter.
August bank holiday has long been regarded as a time to carry out engineering work because passenger numbers are low.
Passengers can sign up for an Advance travel alert with Avanti West Coast.
“Tell us when you’re looking to travel and we’ll email you on the day Advance tickets go on sale,” says the train operator.
Work on the East Coast main line between Grantham and Newark on Saturday 28 August means some evening journeys on the LNER link between London King’s Cross and Yorkshire will be cancelled or diverted.