Passenger groups last night warned of overcrowded trains on the East Coast Mainline as a result of major engineering works being planned next summer.

The Rail Passengers Committee said it feared months of track closures on the West Coast Mainline could have a knock-on effect on the region's main rail link.

It was announced yesterday that planned improvements on the West Coast Mainline, operated by Virgin, will lead in the summer to the 17 week closure of a 40 mile stretch of the line which links London to Glasgow.

A further four month closure of a section of the line is also being planned in early 2004.

Ernie Preston, secretary of the North-East Rail Passengers Committee, said there was a real prospect of passengers transferring to the East Coast Mainline in order to get to Scotland more speedily.

This could lead to overcrowding on some already congested GNER services. He said: "GNER needs to be alive to the possibility of overcrowding and we will be talking to them about it.

"At the moment current services are very heavily loaded up and if there is a transfer across that will only exacerbate the situation."

Mr Preston said there also needed to be a debate about whether it was best to renew sections of track in "dribs and drabs" or over one long continuous period.

Just last weekend Railtrack closed part of the East Coast Mainline in Nottinghamshire, adding about an hour to journeys as passengers were forced to transfer to buses.

Andy Naylor, a spokesman for GNER, said he believed the West Coast Mainline closure would only have a minimal impact on the company.

But he admitted that if passenger numbers did jump it would be struggling to provide more seats especially at peak times.

He added: "We understand there are robust contingency plans in place for the West Coast Mainline and both lines serve different markets anyway." The West Coast Mainline works are expected to shave 35-40 minutes from the current five-hour London to Glasgow journey time by 2006.