HMRC Snooping Methods

From browsing Facebook profiles, to noting careless talk in the pub, to talking to bitter ex-partners, HM Revenue & Customs is watching, snooping and listening. And its investigators will stop at nothing if they even suspect that you’ve been lying on your tax return. Originally published in the Financial Times


When Mike Wells touches a button on his keyboard, a tangle of tiny lines bursts on to his computer screen. Within seconds, it weaves an elongated spider’s web connecting small graphic symbols representing people, addresses, phone numbers, bank accounts and employers.

When he clicks on an icon, another maze of connections ripples across the screen. At a glance, a skilled investigator can detect a pattern of concealment. Wells, director of risk and intelligences services at HM Revenue & Customs, says: “Over time you get familiar with a normal person’s spidergram. When someone is operating in a hidden economy it has a different shape.”

This is the tax authority’s “breakthrough” computer system, a new, powerful weapon against the fraud, evasion and avoidance that costs the Exchequer billions of pounds every year. The system – known prosaically as Connect – was designed by defence contractor BAE Systems and launched in the summer of 2010. It cost HMRC £45m, but even by 2011 it had delivered £1.4bn of additional revenues, according to the National Audit Office. Wells says: “Its power is making it so much harder to hide from us.”

Six out of ten inquiries now make use of the system, with investigators working “hand in hand” with 3,000 Connect analysts in offices up and down the country. It uses a mathematical technique known as social network analysis that ploughs through disparate, previously unrelated information to detect otherwise invisible networks of relationships. It automates analysis that would once have taken months, if it could have been done at all. “If a human being tried to plough through 26 databases, they just couldn’t do it,” says Wells.

Connect is an appropriate name. HMRC has a unrivalled wealth of information about people living in Britain, due in part to its many connections with other databases, such as the Land Registry, Companies House and the electoral roll. “We have more data than the British Library,” says Wells, adding that the HMRC website is one of the world’s biggest websites at peak filing time.

Access to such comprehensive data does not just allow investigators to spot anomalies. It also makes it much easier for HMRC to check up on individuals’ tax returns. Take inheritance tax, where HMRC receives about 300,000 paper returns every year. Around 200,000 of those come from estates claiming to be below the taxpaying threshold.

Using Connect, HMRC can sift through information on property transactions, company ownerships, loans, bank accounts, employment history and self-assessment records to spot where estates might be under-declaring. In its first year it raised an extra £26m in inheritance tax.

However, formidable computing power is not the only way HMRC can spot “invisible” income and underpayment of tax. Here are some of the other methods – some high-tech, some very traditional – that the tax authorities deploy to snare the unwary.


HMRC inspectors have surprisingly wide-ranging powers. They can turn up at business premises unannounced to review records, ask to see documents and request access to computer systems.

Tax inspectors also now operate undercover, in disguise, and in teams to root out suspicious behaviour. Examples include inspectors acting as customers needing hair cuts to gain an understanding of how a salon operates. Other inspectors pose as couples out for a meal at a restaurant. The meal is later checked against the restaurant’s end-of-year books to see whether it has been properly accounted for.

Gary Ashford, head of tax disputes at RSM Tenon, the accountants, says restaurants are a happy hunting ground because of the large number of small value cash transactions that are involved and regular changes of ownership. “Where they do these reviews they are looking at all aspects of taxation,” says Ashford.

Restaurant owners are also supposed to apply income tax and national insurance to tips, but when tips are paid in cash, waiting staff often pocket them while the proprietor turns a blind eye.

Andrew Watt, partner at Watt Busfield tax investigations says: “On the same night as these mystery shopping exercises, inspectors are also likely to have an observation van carrying photographic equipment outside the business, counting the number of people going in or out. If they have seen 150 go in, but the books only account for 100, they could have a case for fraud against the business.”


For all the weapons in its technological armoury, tip-offs are still a vital source of information and tend to generate the biggest returns. Embittered divorcees and disgruntled former employees are among the Revenue’s key sources.

Andrew Watt, partner at Watt Busfield, says: “When I was a revenue inspector we used to get regular letters naming people. If they were anonymous we tended to throw them away. Today, the Revenue keeps this information on file and uses it to cross reference to other information about that individual.”

City law firm Reynolds Porter Chamberlain (RPC) says HMRC paid out 21 per cent more to informers in the tax year to April 2012 than the £309,620 in the previous year.

“HMRC is under intense pressure from the Treasury to increase the tax yield for the Exchequer and it is increasingly resorting to unorthodox methods to get the job done,” says Adam Craggs, tax partner at RPC. “Other informers include those reporting someone bragging in the pub or doing a lot of jobs cash-in-hand.”

Watt said one example of a tip-off from an informer was a disgruntled ex-wife of a trader, who told the Revenue about her ex-husband’s offshore account to make trouble for him.

Rewards vary from a few hundreds to tens of thousands of pounds, but are paid only once tax has been recovered – and payments are not a fixed percentage of the tax recouped.


The “chi squared” test is another tool sometimes used by inspectors to check the reliability of reported figures, including restaurants’ sales figures. This test, also known as Benford’s Law, is a means of testing the randomness of figures. In many real-life sources of data the number one occurs as the first digit about 30 per cent of the time, while larger numbers occur less frequently.

Unaware of this finding, fraudsters are likely to choose numbers that do not fit this pattern. Derek Allen, tax director of ICAS, the Scottish accountancy institute, says he first came across inspectors in Scotland using this test in 2003, when an inspector claimed that a restaurant’s sales were fabricated. But he queried the logic that a restaurant’s results should be random, describing it as a “pseudo scientific” argument.


HMRC has recently beefed up its powers to demand “bulk” information from businesses or government agencies. In 2008 it homed in on the medical profession, acquiring information from National Health Service trusts, private hospitals and medical insurance companies to test its suspicions that practitioners were failing to declare fees for consultations, medical examinations and other services.

Plumbers and heating engineers have also been targeted, after HMRC obtained information from the Gas Safe register. This trawl resulted in five arrests.

Gary Ashford at RSM Tenon, a professional services firm, says the tax authority’s access to Land Registry and DVLA data means it knows how much someone has spent on their house and can see vehicles registered to each address. He says, for example, that if someone has bought a Ferrari but is living in a modest flat, that might not fit with that individual’s financial affairs according to the Revenue. Or if someone owned three properties in their name but had not declared any rental income, that would also be a warning sign.

Ashford adds: “This allows the Revenue to build up a picture of someone’s financial worth and means that if someone is only declaring £20,000 a year, but is living a £100,000 lifestyle, HMRC can call on that individual to pay more.”


In certain circumstances, inspectors now have the power to raid the homes of people they suspect of not paying tax. They did this 499 times in the tax year 2011-12, according to Pinsent Masons, the international law firm. That was a 155 per cent increase on the previous year.

These property searches, which tend to focus on individuals who run their businesses from home, relate to the Revenue’s aim of increasing criminal prosecutions fivefold by the 2014-15 tax year. “We are already seeing positive results from these increased investigations and searches: during 2011-12, criminal investigation activities resulted in 545 individuals being charged and 413 being convicted, with a success rate in court of 92 per cent,” HMRC said.

Accountants say investigators are focusing on lawyers, plumbers, teachers and doctors – essentially anyone who failed to take advantage of recent “disclosure opportunities” to declare income.


The Revenue also gets information from less obvious sources, such as adverts on noticeboards in newsagents, stories in local newspapers, and even social networking sites, such as Facebook or Twitter.

Mostly, inspectors are looking for evidence of a lifestyle that’s out of kilter with declared income. If the Revenue has doubts about someone’s tax affairs they will search for any information they can find on that individual, including posts on Facebook and tweets.

“If HMRC reads a story about an expensive wedding in the local newspaper and it involves the daughter of someone who claims not to earn very much, that might set alarm bells ringing at the tax office,” says Watts.

“Similarly if someone is constantly putting up pictures of expensive holidays and flashy cars on Facebook, but is paying minimal tax, then that could also trigger an investigation.”

He adds that several individuals were caught out after appearing on the Channel 4 television programme My Big Fat Gypsy Weddingspending thousands of pounds of undeclared income on lavish family weddings. Another individual came under HMRC’s watchful gaze after posting photos of their luxury holidays on Facebook.


Higher-rate taxpayers with properties abroad are among those targeted by the 200-strong “affluence unit”, which is dedicated to checking that those who pay the 50 per cent tax rate, but are worth less than £20m, are complying with tax law.

The team uses “sophisticated data mining techniques” on publicly available information to identify individuals who own property abroad. It then uses risk assessment tools to highlight those who do not appear able to afford those properties legitimately as well as those who have not declared the correct income and gains from the property.

The affluence unit has been set a target of raising an extra £560m over the next four years. As well as overseas property, other investigations involve commodity traders and people holding offshore accounts.


As tax authorities around the world redouble their efforts to collect more tax, cross-border co-operation is becoming much more common, with various agreements struck with tax havens such as Liechtenstein and Switzerland.

HMRC is gaining access to much more information from offshore centres; in 2006, a landmark legal ruling forced Barclays and other high street banks to hand over records of customers with offshore accounts. A rash of leaks – most recently from HSBC Jersey – has also put previously secret data about offshore accounts into HMRC’s hands.

“International borders are increasingly meaningless for tax authorities’ pursuit of outstanding taxes,” says Berwick.

The number of requests for information about taxpayers received by the UK government from overseas tax authorities surged by 18 per cent in the past year. Phil Berwick, director at Pinsent Masons, says: “Tax authorities around the world are responding to pressure from their governments to maximise their tax revenues. It is not just HMRC that is piling the pressure on taxpayers.”


HMRC’s advertising campaigns are designed to make tax evaders feel rotten about cheating the Exchequer when times are hard – and to emphasise that the net is closing in. The latest adverts warn tax cheats to declare all their income “before it is too late”. It is also “naming and shaming” individuals who evade more than £25,000 in tax. It publishes lists on its website quarterly that include the person’s name, address, nature of business, period covered by the evasion, amount of evaded tax and the penalty for that evasion.

Accountants say the current war on tax evaders represents the first time that HMRC has taken such a wide approach to tax evasion; previous campaigns have focused on individuals in high-risk business sectors, with tax amnesties and taskforces being used as carrot and stick.

“As it stands, HMRC isn’t missing any tricks when it comes to collecting this extra revenue,” says Roy Maugham at accountancy group UHY Hacker Young. “The targets it has been set are extremely high, and HMRC is really focusing all its energy into ensuring it meets them.”

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