Three rail unions are launching a legal challenge to put the brakes on the coalition privatisation of East Coast Main Line, Britain’s only publicly-owned inter-city rail service.

RMT, Aslef and the TSSA are seeking a judicial review over any sale of the line, which links London Kings Cross with Edinburgh via centres such as Peterborough, Doncaster and Leeds.

The service was privatised in 1996 but taken back into public ownership in 2009 when incompetent contractors National Express Group proved incapable of operating it efficiently despite receiving millions in taxpayer subsidies.

Under public ownership it has delivered around £800 million to the Treasury.

It has also won passenger approval ratings which make it the most efficient and popular inter-city rail service in the country.

The Tories and their Liberal Democrat collaborators are openly manipulating the tendering process to rush through privatisation before next year’s general election.

RMT acting general secretary Mick Cash said it was “shocking” that the government was trying to “hand the East Coast Main Line back to their friends in big business” so soon after robbing the British taxpayer of a billion pounds in the scramble to privatise Royal Mail.

The unions say privatisation is against the interests of rail workers, taxpayers and passengers alike.

Another objection is lack of public consultation.

Even though an independent review recommended that the procurement process take place over 24 months, the government plans to shorten it to 15 months to hasten privatisation and complete it by February next year.

Aslef general secretary Mick Whelan said, “It is imperative that we raise the genuine concerns of all stakeholders but, especially, the employees before this is rushed through.

“We cannot, in good conscience, allow the mistakes of the past to happen again.”

TSSA general secretary Manuel Cortes added: “The Tory-led coalition knows only too well that rail franchising is not fit for purpose. They continue to ignore the recommendations of the Brown review which they commissioned following the West Coast debacle.

“Rail workers are at a loss to understand why the government insists on going forward with a broken system which threatens the interests of passengers and taxpayers. We can only conclude that the ideology which saw Royal Mail flogged off on the cheap continues to thrive.”

The unions are also challenging the government’s decision to award First Capital Connect an extended franchise for Thameslink and Great Northern services without any tendering process or consideration of whether passengers’ and workers’ interests would be better served by taking the service into public ownership.