SOUTH West Trains is now renewing its ageing fleet on the Southampton and Bournemouth lines.

The move will see it replace all of its 20-year-old class 442 trains on the Weymouth to Waterloo line with modern class 444 Desiro trains, pictured.

The 24-train replacement programme on the line will be completed in February, but has attracted criticism from rail users and a local MP.

South West Trains said that it carried out a review of capacity across the network to "make sure it provides as many seats as possible where they are most needed".

A spokeswoman said that the train replacement was not a cost-cutting exercise.

"Our leasing costs will have increased by a considerable amount," she said.

She said that customers would benefit from more standard seats, an increase of 18 to 299 on five coaches, on-board CCTV, power sockets in first class and curtains.

However Denis Fryer, of the South Hampshire Rail Users group, said that the seats were harder, the air conditioning noisy and there were fewer tables with the blocks of four seats favoured by families.

The class 444 also has 15 fewer first class seats, he added.

Eastleigh MP Chris Huhne also criticised the decision to replace the class 442 units, which he said could have remained in service until 2020.

"It is ridiculous, given the desperate need for more trains in this country, that these efficient, popular trains will be left getting rusty in the sidings," he said.

South West Trains renewed its franchise last year, agreeing to pay the government £1.2bn over ten years.

The company is planning to shed about 50 jobs at the Bournemouth depot where the class 442s are maintained, through 17 voluntary redundancies and other relocations.