Ministers' shady plans to reprivatise the successful East Coast Main Line under a barrage of misinformation were leaked to transport union RMT yesterday.

The union got access to the sale prospectus for Britain's most successful line days before it was published.

It was leaked as rail campaigners lobbied Parliament, handing in a 23,000-signature petition demanding that the service stay in public hands.

RMT said the prospectus is a blueprint for rip-off prices, reduced services and huge profits.

ECML was taken under public control in 2009 after privateers failed miserably to operate it efficiently or viably.

Under public control it has brought £600 million to the Treasury, increased passenger numbers, improved efficiency and put private operators to shame.

But the Tories and their Lib-Dem collaborators plan to force through reprivatisation before the 2015 general election with a franchise that could last for 11 years.

The prospectus's main aim appeared to be to cover up the service's success under public ownership, including high levels of punctuality and the highest passenger satisfaction rate of any main line service in Britain.

The dodgy dossier also takes pains to remind privateers that the new fleet is compatible with driver-only operation - offering a green light to sack safety-critical on-train crew.

The union described the document as "the most blatant and cynical piece of political engineering to try and justify hiving off the line for private gain."

It said: "The draft prospectus gives bidders the option of establishing an 'intermediate class between standard and first' - opening up the route to offering a third-class service."

RMT general secretary Bob Crow said: "This leaked document, coming on the day of union protests at Parliament aimed at keeping the East Coast in public ownership, is political dynamite which blows the lid off the lengths to which the government are prepared to go to bulldoze through reprivatisation before the next election."