The state-run East Coast rail service requires less public subsidy than any of the 15 privately run rail franchises in Britain, according to a report from the rail regulator.
The report comes after the coalition government pledged to push the London to Edinburgh line back into private hands before the next election, with a new operator taking over by February 2015.
The route has been under the control of the Department for Transport since November 2009 after the transport company National Express pulled out.
While about half of all train operating companies paid premiums to the government last year, the report shows that passengers on every franchise were in effect subsidised when money spent on infrastructure was included. However, the net subsidy for East Coast was 1% of the line's income, compared with an average of 32%.