An anonymous "disillusioned" Tory voter has splashed out an estimated £16,000 for a full-page advert in the Times to beg David Cameron and George Osborne to learn about the "unpleasant realities of the real world".

The advert in Tuesday's Times takes the form of a letter to the prime minister and the chancellor and is signed simply as "Martin, full name and address supplied".

"Martin" takes Cameron to task over the ballooning national debt and gives him a three-point plan to get the economy working again: get rid of a quarter of all senior civil servants; remove unnecessary health and safety departments; and review all capital expenditure projects whose return does not materialise for several years. He suggests that only capital expenditure projects that have at least 50% UK labour content should be considered and warns that bolting foreign trains together in a British plant "is hardly the same".

News International declined to divulge the advertiser's identity, but said the advert was placed by "an ordinary individual who was not affiliated to any party or any company". The cost of a black and white full-page advert is £16,645 according to the company's website, though this "rate card" price is not likely to have been paid.

The ad appears on page 20, opposite Nigel Lawson's opinion piece calling for the UK to leave the EU.

The Times ad (click for full-page image)

"Martin" calls on Cameron to drop the soundbites and do something to "sort out the banking system, to curb wealth-destroying civil servants and to cut debt and our deficit".

He also takes him to task on his boasts about the 1 million jobs he has created. "It is offensive to those desperately looking for employment," he says.

But he also has some advice for Osborne, who he says has "done even less than Mr Cameron". He tells him he has failed to get to grips with the banking crisis and says he should try and find out what the banks in Germany, Singapore or Malaysia are "so much more helpful".

He is excoriating about the Financial Services Authority which he says was there to protect the citizens "from the excesses of the banks" which it has "failed ... on nearly every count".

"Renaming the FSA and changing a couple of people does not make a new organisation," says Martin.

Some industry wags wondered whether the advert might have been placed by Sir Martin Sorrell, the boss of marketing and advertising giant WPP. However it is unlikely given the advertiser's specific references to health and safety in relation to the construction industry, a more likely source of the letter.

If the letter led to some initial schadenfreude in Labour HQ, it was misplaced. Martin signs off by throwing a few punches towards Ed Miliband and Ed Balls, telling them there is "no reason to suppose that you would do any better".

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