The government knew Northern rail passengers would face major disruption two years ago, an MP has claimed.
Wigan MP Lisa Nandy said she obtained Department for Transport (DfT) emails which discussed “propagating myths” to divert attention from route closures.
At Prime Minister’s Questions, she said the messages were a “disgrace”.
Theresa May refused to comment on “leaked” documents, though it later emerged they had been obtained via a Freedom of Information request.
Responding to Ms Nandy’s allegations, the Prime Minister said a panel was set up to advise the DfT about the plans.
She said the emails show how “officials describe key Northern routes as valueless, discuss classic handling strategies for members of Parliament, discuss whether to throw a sop to Northern passenger groups and debate whether to propagate myths in order to divert public attention from agreed planned route closures.”
She asked why the government had “withheld this key information” from the house and the public.
Ms Nandy also tweeted some examples of the correspondence involving the line between Wigan and Southport.
A new timetable was introduced on 20 May and Northern passengers have faced widespread disruption and cancellations.
The emails “are nothing to do with the current timetabling issues” and the “excerpts quoted relate solely to a decision”, about a particular route with “no further implications beyond that individual route”, a Dft spokesman said.
“It is deeply regrettable that a DfT official used inappropriate language and that matter is being looked at,” he said.