Access consultant David Burdus, 44, said he asked GNER staff for a carriage with a disabled toilet when he booked his ticket from Tyneside to London.

But he said he found himself in an area without disabled facilities and had to use a glass to relieve himself.

In a statement, GNER managers pledged to investigate.

Mr Burdus, from Corbridge, in Northumberland, blamed poor communication within GNER for the affair.

Improving facilities

He said: "I ask GNER not to put me on a train if they know it does not have an accessible toilet.

"So they put me on one that does not have an accessible toilet. I obviously had to go to the toilet and had no choice but to go into the lobby and use a glass."

Mr Burdus, who was a consultant on disabled access at the Sage Gateshead music complex, claims he raised the issue with GNER staff at the time, but was ignored.

In a statement, GNER said it was committed to continually improving facilities for disabled people.

"We have installed additional easy access toilets and as a result these are now available on every GNER train," it said.

It said Mr Burdus was given a customer comment form and his comments would be considered.