Labour's transport chief has delivered a savage dig at her Tory rival after the Government froze rail fares in the Budget . Heidi Alexander lashed out at Richard Holden, who made a "chicken run" from the north to a seat in Essex shortly before the general election . In the build-up to last week's Budget, Mr Holden wrote to Ms Alexander calling on her not to raise fares by more than the Retail Price Index (RPI), which is used to measure inflation. Instead Chancellor Rachel Reeves announced there