NEW state-of-the-art trains set to come into service later this year will not be stopping at a popular Hampshire station - because they are too long.

Commuters were meant to be speeding up to London on the new Siemens Desiro 444 electric trains, due to enter service on the route in December.

But the platforms at Portchester station, near Fareham, are not long enough to accommodate the new five-carriage trains with their sliding doors.

It means Portchester passengers will have to change at Fareham to go to London.

South West Trains (SWT), which was initially awarded a 20-year franchise for the service, says it had planned to extend the platform at Portchester when it invested £645m in the fleet of German-made trains.

But the Strategic Rail Authority (SRA) cut SWT's franchise to three years in a bid to improve its performance.

SWT bosses now say they are not prepared to invest the £1m required for the platform extension when they could lose the contract.

The SRA claims it cannot afford to lengthen Portchester's platforms either.

Passenger representative groups and environmental groups have labelled the situation as "ridiculous".

Geoff Bignell, vice-chairman of the national Rail Passengers' Committee, laid the blame at the door of SWT.

He said: "I think it's ridiculous. The whole thing is a complete farce. They should be saying 'How can we best serve the passengers?'

"It's nothing to do with the SRA, it's SWT who bought the trains."

Meanwhile, John Vivian, of Gosport and Fareham Friends of the Earth, labelled the situation "a fiasco".

He said: "We welcome the new trains but is this just another example of the benefits of the privatisation of British Rail?"

SWT purchased 177 of the new electric Siemens trains to replace its ageing slam-door vehicles, which could stop at stations whose platforms were too short.

New health and safety guidelines prevent the new generation of trains doing this.

SWT spokesman Jane Lee said it was not a fault of the trains but a fault of the platform length.

She said: "The SRA has decided it cannot justify lengthening the platform so that means the people of Portchester would lose their through trains.

"We are undergoing consultation on the timetabling. We have asked South Central services to make additional stops."

An SRA spokesman added: "Given the financial constraints currently faced by the industry, we have no plans at present to extend the platform. We are in discussion with SWT on how we can address passenger concerns."