High-speed rail services have been cancelled across the UK after hairline cracks were found in Hitachi trains.
Hitachi 800 trains used by London North East Railway (LNER), Great Western Railway and Hull Trains have been found with the issue.
All LNER routes from London Kings Cross to Aberdeen have been cancelled, while Great Western trains in and out of London Paddington are also out of action.
There are currently more than 90 cancelled trains across both rail services as the cracks are being investigated.
LNER services on the east coast between London, York, Newcastle and Edinburgh have been stopped.
And there are no Great Western services between London, Bristol, Cardiff and Penzance.
Hitachi 800 trains used by London North East Railway (LNER), Great Western Railway (pictured) and Hull Trains have been found with cracks, seeing services cancelled across the UK
It is not known how long Hitachi's investigation will last and passengers are warned to check before travelling.
Great Western Railways said: 'A number of Class 800 series Hitachi trains from several train companies have been taken out of service this morning for checks as a precautionary measure.
'As a result we have had to cancel a significant number of long distance train services to and from Paddington, and while local services are running, we expect them to be very busy.
'This problem is being investigated by Hitachi and once trains have been checked and cleared, we hope to be able to release them back into service as soon as possible.'
Open tickets for LNER customers travelling between London Euston and Manchester will be accepted on Avanti West Coast services.
And people travelling between London and Sheffield can use their LNER tickets on East Midlands Railway services while the issue is being investigated.
LNER services on the east coast between London, York, Newcastle and Edinburgh have been stopped
LNER said: 'We are experiencing significant disruption to our train services due to more trains than usual needing repairs at the same time.
'Because of this, we're advising customers not to travel today.'
Hull Trains said the problem is being investigated by Hitachi and trains will be released back into service 'as soon as possible'.
A spokesperson said: 'This could affect a significant number of our services and passengers should check before they travel.'
And TransPennine Express said its Nova 1 trains had been affected by the issue and were being checked.
It advised customers not to use the Newcastle to Liverpool route today.
In a statement, a TPE spokesman said: 'This problem is being investigated by the train manufacturer and once trains have been checked, we hope to be able to release them back into service as soon as possible.
'This will affect a significant number of services on our Newcastle to Liverpool route and we are advising customers not to travel on this route today.'