Would-be North East Somerset MP Jacob Rees- Mogg said last night he was "embarrassed" and sorry after being caught out plagiarising The Sun in a letter sent to potential voters.

The City fund manager and son of former editor of The Times William Rees-Mogg sent the letter to constituents criticising Gordon Brown for his failings over the economy.

But entire sections of the letter signed by the Tory parliamentary candidate for North East Somerset had been nicked from an article published by The Sun's associate editor Trevor Kavanagh in December.

The signed letter was sent to prospective voters in January, and then put through doors from Radstock to Keynsham last month.

The former Etonian admitted yesterday he had not, in fact, written any of the letter, and left it to "someone else" to do it for him. That person, he said, was to blame for plagiarising The Sun.

They had done a little bit of their own work – replacing the odd reference to "Britain" with "North East Somerset", and working out how much of the nation's total debt was shared out in his prospective constituency.

After copying word for word a sentence about the Government's budget, The Sun version labelled it "a costly flop", while Mr Rees-Mogg's letter changed that to "both expensive and trivial".

Last night Mr Rees-Mogg said he would apologise to Mr Kavanagh.

"Though the piece expresses my views, I didn't specifically write it, although I agree with the points made," said Mr Rees-Mogg. "Some of the text is just points that anyone would make and have been a standard feature of any number of Conservative leaflets.

"While the points are valid, plagiarism is a bad thing and I will drop a note to Mr Kavanagh apologising, and we won't ask the person who did write this to write for us again. It's embarrassing and a matter for which I apologise.

"Most of the points made here have been made in many, many different places and it's just a convenient way of putting things."

Radstock resident Terry Reakes, a long-time Labour councillor, said he was amazed Mr Rees-Mogg had copied from The Sun.

"Plagiarism is always appalling, whether it's done by a schoolboy at Eton or a comprehensive school, but when it's done by someone who wants to be an MP, it's even worse," he said.

"He's got every right to criticise the Government, but given that he's a major fund manager in the City and his dad's a newspaper editor, surely he's capable of giving his own assessment of the state of the economy without borrowing from The Sun.

"This is appalling – he should be the one telling the newspapers what he thinks, not the other way around."