After doctors, the Revenue turns on vets and lawyers

Tax officers are also concerned doctors may be living as far away as Spain and claiming travel to Britain to see patients.

David Marples of Abbey Tax, which insures accountants for the cost of client audits, said: "We've seen surgeons and anaesthetists investigated in recent months. One cardiothoracic surgeon was pursued for 80% of his claim for home to office travel going back years costing many thousands of pounds. We settled with a tax bill of just £1,000 going back one year."

Accountants said that to target just one profession was "unprecedented" but they fear more sweeps are planned - the Revenue has set up a so-called Barrister Unit at its Euston Tower premises in London to pursue barristers and their clerks, while accountants have noticed vets in Bristol and the southwest are being increasingly pursued for undeclared private practice income and expenses.

Stephen Camm of Price Waterhouse Coopers, the accountant, said: "The hot tip is certainly that barristers are next. It makes sense as they, like doctors, are in private practice with opportunity to divert from the Revenue. There are Harley Street doctors, for instance, who put a third of their income into Swiss accounts."

Tax collection tactics have been growing ever more aggressive. Investigations jumped 21% to 900 in the second half of 2009 compared with the first, according to Abbey Tax, as the taxman stepped up the hunt for lost revenue. Private sector debt collectors have been drafted in to help while Revenue inspectors have been accused of breaking HMRC guidelines.

Angela Beech at Blick Rothenberg, the accountant, said: "In one case we've seen, an inspector began asking questions of the neighbours when the taxpayer wasn't home. Another inspector suggested a client use his credit card to pay a tax bill before seeking advice on whether the investigation was even warranted."

We answer your questions about the latest tax attack.

How does the doctors' amnesty work?

Doctors have just two months to notify HMRC if they wish to make voluntary disclosures of any unpaid tax owing. A reduced fixed penalty of 10% is being offered for "full and accurate" disclosures, compared with up to 100% in normal circumstances.

The medical profession is under the spotlight for failing to declare fees - for instance, the fee known in the industry as "ash cash" that is earned for providing a medical certificate before a cremation, worth about £70 each time. Doctors are also in trouble for claiming their home as a place of business, on the basis that they undertake paperwork there, while deducting as expenses the cost of travelling from home to the hospital or practice rooms.

The Revenue has indicated that doctors cannot claim their home as a place of business if they do not see patients there.

Where the income is offshore and should have been disclosed under the previous amnesty, doctors will face higher penalties. The deadline for notifying HMRC of an intention to make a disclosure is March 31. The disclosure itself then has to be made by June 30 on the forms available at hmrc.gov.uk/tax-health-plan.

How does this relate to the offshore amnesty?

HMRC was forced to go to court to compel banks and building societies to hand over information about potential customers with undeclared income in offshore accounts. It can now order third parties to disclose such details under its new powers.

The first offshore amnesty, known as the offshore disclosure facility, ran from April 17, 2007, to June 22, 2007, and encouraged 40,000 people to come forward, raising £400m in tax. A second offer - the new disclosure facility - ran from September 1, 2009, to January 5, 2010, with about 13,000 people thought to have come forward.

What about other professions?

The amnesty has been criticised for giving doctors the "cheap option" while others face higher fines. The Institute of Chartered Accountants of Scotland mounted a defence of fish and chip shop owners who it said had been "battered" by HMRC while doctors were given an easier ride.

The Revenue has said that launching an amnesty is more cost-efficient than opening thousands of inquiries.

What to do if an inspector calls?

It is unlikely that HMRC will tell you what it is targeting, so advisers urge taxpayers to start by asking what you have done wrong.

Marples said: "You have the right to challenge any area of contention - the inspector is not always right."

Last year, a statutory ban on inspecting purely private dwellings without consent was introduced and a statutory requirement for HMRC to give at least seven days' prior notice of a visit, unless either an unannounced visit is "necessary", or a shorter period is agreed. Unannounced visits must be approved beforehand by a specially trained Revenue officer.

However, the burden is on the taxpayer to prove that the source of income is either tax-exempt, or has been declared lawfully.

You can appeal against any HMRC order to the independent appeal commissioners within 30 days. If you are being investigated and want to see the documents held on you, call the HMRC Data Protection Unit on 0191 225 7575.

What can you do in advance?

Keeping accurate records will make an inspection less painful. There are also insurance policies that reimburse fees for investigations, such as those from Abbey Tax and Qdos.

WELCOME TO MY TAX HELL

Nick Morgan, an author and freelance journalist from Brighton, is one of a growing number of middle-class professionals forced to justify the expenses he claims on his income tax self-assessment return.

HM Revenue & Customs opened an investigation into Morgan - pictured with his children Finn, 5, and Dan, 2 - in July 2005.

Morgan, 41, claimed expenses of just under £4,000 for newspapers, used for research, and travel to London. However, the taxman initially said he could claim just £1,000. When he argued his case, the figure he could claim rose to £3,000. Morgan was also incorrectly accused of receiving £325 of undeclared payments.

"They spotted a cheque and didn't believe it was a birthday gift from my mother. I had to write to ask her for copies of her bank statements."

Morgan has written an e-book at tax-hell.co.uk.

BEWARE THE ONLINE RUSH

Taxpayers have been urged to file their online returns as soon as possible, with a record number expected to do so this year. HM Revenue & Customs' site has been known to crash under the weight of late submissions.

More than 9m are required to file their self-assessment forms and pay any tax due by January 31 - two weeks today - or face a £100 penalty charge.

Bear in mind that it can take more than a week to register to file online. Go to hmrc.gov.uk/sa and click on "register for self-assessment online". You will then have to wait for an activation PIN, which may take seven days to arrive.