MP Oliver Letwin has joined the row over whether a Dorchester school is to get a new extension.

Governors at Dorchester's Manor Park First School have slammed education bosses after it was revealed that a proposed new extension for the school had been shelved.

They said the school was reaching bursting point after council chiefs pressed them to take on more pupils with the incentive that new classrooms would be built.

And if the extension was not built, governors claimed they would be forced to either have mixed aged classes or squeeze the children into classes of 36 to 38 per class.

Mr Letwin has written to the director of education at Dorset County Council, David Goddard, to express his concerns about the growing crisis.

He said: "I have been approached by constituents who are concerned about what appears to be a serious misunderstanding about the provision of extra accommodation at Manor Park School in Dorchester.

"I believe it is common ground that there is a serious problem of overcrowding in this school and there was clearly a very strong expectation on the part of the school that extra accommodation would be considered in a second phase extension.

"I understand that it is now believed by the governors that the second phase of the extension may not be forthcoming.

"I gather that Councillor Trevor Jones does not feel able to participate in the discussion of this particular problem due to a conflict of interest.

"I am accordingly writing to you in order to make you fully aware of the concerns of some of my constituents and in the hope that you and your colleagues will be able to allay fears of the governors of the school."

Keith Armstead, senior education officer and head of premises said the LEA needed to bid for a share of £50m from the government to pay for the extension.

"We need to bid for a share of that money and if we are successful the new classrooms would be built by September 2002.

"However we will need to demonstrate that the classrooms are needed."