The government is coming under intense pressure to either abandon or fix the “grossly unfair” retail prices index inflation measure, which MPs say is penalising students and rail passengers. In a rare combined letter from parliamentarians in the House of Commons and the House of Lords, RPI was described as “absurd” and its continued use was labelled “a ridiculous merry-go-round”. In the letter sent to the head of the UK Statistics Authority, John Pullinger, the House of Commons Treasury select…