RAIL Minister Lord Adonis said today that there was ''no question'' of cash-strapped companies being allowed to re-negotiate their contracts.

It is believed that transport giant National Express wants to alter its contract terms for running the East Coast Main Line, which involves the payment of £1.4 billion premiums to the Government.

But Lord Adonis stressed today that no train company was at present in default of its contractual obligations, and that National Express was continuing to keep up its premium payments for East Coast.

He went on: ''There is no question of contracts being re-negotiated, but no company has told us that they are in default of their obligations.

''The situation is that National Express is continuing to make its premium payments.''

Asked if National Express was in discussion about its East Coast contract with the Department for Transport, Lord Adonis replied: ''We talk to train operating companies all the time.''

Today, transport union the RMT is launching a political campaign aimed at securing the re-nationalisation of the East Coast line, with the union describing National Express as ''debt-ridden''.

RMT general secretary Bob Crow said: ''The chaos facing the rail industry from the looming collapse of major franchises is unprecedented, and we are calling for the Government to step in now and begin the process of re-nationalisation to restore order to the railways.

''It would be political suicide for the Government to bail out National Express and offer a copper-bottomed management fee guarantee in return for ripping up the East Coast franchise.''

Lord Adonis was speaking at Euston station in London, as he officially opened the £8.9 billion West Coast Mainline upgrade, which actually was completed last December.

Lord Adonis also opened a new Virgin Trains ticket office at the station.

Train journeys between London and the Midlands, the North and Scotland have been reduced since the massive upgrade programme was completed.

However, travellers still suffer disruption at bank holiday weekends due to continuing engineering work.

In the spring bank holiday weekend coming up, buses will replace trains between Milton Keynes, in Buckinghamshire, and Birmingham for much of the weekend.