Ministers have already agreed with operators to increase train fares by at least 6% in the coming years, Labour has claimed.
Speaking during transport questions on 23 February 2012 shadow transport secretary Maria Eagle insisted the government was too close to "vested interests" in the railway industry.
But Transport Minister Theresa Villiers, appearing at the despatch box for the first time since breaking a collar bone in a cycling accident, labelled the claims "disingenuous" - earning herself a rebuke from the Speaker for using un-parliamentary language.
Opening her questioning, Ms Eagle told Ms Villiers: "You seem to be saying one thing to the train companies and another to passengers. I have the invitation to tender for the West Coast Mainline.
"It promises figures that they can increase fares by up to 8% above inflation next year, up to 8% above inflation the year after, and then by up to 6% above inflation every year for the rest of the entire 15 year franchise.
"It seems the decision has been taken. When are you going to stand up to these vested interests and stand up for passengers?"
Ms Villiers replied: "You have resorted to this same old stuff about the fares basket flexibility that Ed Miliband got completely wrong in prime minister's questions. This was a fares basket flexibility that Labour suspended for one year and then re-introduced.
"This is flexibility the Labour administration in Cardiff is still using. It is entirely disingenuous for you to get up and talk about..."
Speaker John Bercow then intervened, telling the transport minister: "We don't use the word disingenuous in the chamber and I'm sure you're happy to withdraw it and we are grateful for your answer."
Bookmark with:
What are these?
E-mail this to a friend