As a state-owned service East Coast was incontrovertibly a success.

Taken over by the government as a last ditch measure in 2009, the rail operating firm returned a sizeable profit to the taxpayer, while boasting some of the best customer satisfaction levels in the UK. Given the problems experienced by previous operators of the line, passengers breathed a sigh of relief.

On an ideological level, the current coalition government was never likely to make the arrangement permanent and from Monday, passengers on the east coast mainline will begin to see the Virgin livery, as Virgin Trains East Coast takes over the routes.

Some have described the decision to reprivatise the service as disgraceful. Edinburgh's Waverley Station will be one of three terminals to see union-led protests against the move tomorrow. According to some polls as many as two-thirds of the public would wish to see it remain in public control, and almost as many would like to see the rest of the network renationalised.

Critics point out that privatisation policies founded on the principles of consumer choice and competition have now led to a situation where passengers can choose between Virgin on the East Coast and Virgin on the West Coast.

Certainly the success of the state-run East Coast poses a challenge for the new franchisees, raising the bar for the private train operating companies.

Rail privatisation, as delivered over the last 20 years has in many ways been a disaster, a complex mess in which any benefits of competition have largely been squandered through a lack of rigour in assessing bids and a subsequent willingness by government to bail out companies which fail.

The franchise system allows contracts to be removed from failing companies in principle, but if the bidding system encourages firms to make pledges while budgeting too little to afford to keep them there is a problem. That is only exacerbated if government is then too willing to step in to bail them out when they get into trouble.

Only recently have there been signs that the problems are being rectified and that the system might be able to deliver on promises to passengers. That progress must continue to be made.

Change is happening north of the border too, as Abellio is to take over from First Group a month later having won the Scotrail franchise. Like Virgin East Coast, the Dutch firm is promising improvements to infrastructure, services and rolling stock.

Both companies will need to convince us they can deliver as they take over from predecessors who appeared to be performing reasonably well.

In particular, given the East Coast line's troubled history, Virgin must not fail. If the company attempts to come back later cap in hand, both it and the government will be fiercely criticised.

The clamour for nationalisation will only grow unless private operators can convince passengers. The bad old days of British Rail, where public ownership came to be equated with discomfort, unreliability and poor catering, are gone now. The success of the state-run East Coast Main Line is an example which can serve to drive private operators to achieve better.