British prime minister David Cameron has pledged a real-term freeze on nearly half of all rail fares during the general election campaign.
The Tory politician said the move would save an average rail commuter £400 between now and 2020.
The move, which would extend a freeze currently in place, would cover regulated fares.
These fares cover about half of all tickets sold, including season tickets and off-peak intercity returns.
A restriction limiting rises in these fares to RPI (retail prices index) inflation has been in place for the past two years under the coalition government.
Cameron said: “The cost of commuting is one of the biggest household bills that hard-working families face and it is something we are determined to bear down on.”
However, the Liberal Democrats said they had fought in government to keep rail fares down while the Tories “repeatedly argued” for above-inflation increases.
Rail fares in the UK have increased at above the rate of inflation each year for the past decade.
Labour quickly called the pledge “unfunded, uncosted and totally unbelievable”.