Rail minister Claire Perry has defended the Government's decision to reprivatise a key London to Scotland rail line.

She said the necessary investment needed on the East Coast main line could not be made with the franchise being run in the public sector.

Returning the line to the private sector - as Virgin Trains East Coast - was a good deal for taxpayers and passengers, Ms Perry added.

From November 2009 until yesterday, East Coast was run under the control of the Department for Transport.

Its reprivatisation has been bitterly opposed by trade unions, with Labour also questioning the decision.

Speaking at King's Cross station in London where Virgin showed off a train in new East Coast livery, Ms Perry said: "Directly Operated Railways (the company set up by the Department for Transport) were not making the sort of investments required.

"This is a better deal for taxpayers."

She continued: "If the lights are about to go out we know that the Government can step in take over. But the economics of the franchise did not allow for the sorts of investment that we are seeing. What we see today is the best of the private sector. Let's stop talking about the ideology."

Passenger Focus has expressed concern at the decision of Virgin to phase out the Rewards scheme for East Coast passengers and replace it with a Nectar points loyalty scheme instead.

Passenger Focus said this move would "greatly reduce" the benefits on offer.

But at King's Cross today Virgin Trains East Coast managing director David Horne said research among passengers had shown a lot of people were unaware of the Rewards scheme and said they wanted a scheme that they were already in, such as Nectar.

Answering questions from the public at an event in Brighton, Labour leader Ed Miliband branded the Government's approach "nonsense" and insisted East Coast had been "better off" in public hands.

"This government has been doing rail re-nationalisation by the back door, but the re-nationalisation has been for companies from Europe," he said.

"So if you are a European public company you can actually bid for the British franchise, but if you are British public company you can't bid for the franchise. This is just absolute nonsense.

"We are going to have an enhanced role for the public sector in relation to our railways, the only stipulation has got to be value for money."

He added: "I believe East Coast was better off in public hands, I think it would be better in public hands."