Selected taxpayers could shortly be receiving a letter from HM Revenue & Customs suggesting that they may have not paid enough tax, warn Birmingham-based tax specialists from Grant Thornton.
Heather Taylor, senior tax manager at the firm, explains that HMRC ran a pilot project last year in which it sent informal letters to people who held bank accounts or properties overseas suggesting they might not have paid enough tax.
The letters invited recipients to reconsider their position when they next submitted a tax return.
"The aim of these informal letters was to get people to pay more tax, without the Inspector having to undertake a time consuming and expensive formal investigation," Ms Taylor said.
Her colleague Gary Ashford added: "The letters were informal yet to the point, leaving the recipients in no doubt that the taxman was watching them.
"Anyone receiving such a letter was told that they were not under formal investigation, but that the Inspector expected to see higher profits or income in the next return and to be given full details of all investments and earnings in the UKand overseas.
"If no response was made to these informal letters, a formal investigation was very likely to follow - a time-consuming and stressful event for the taxpayer - because HMRC tends to assume guilty until proven innocent.
"It is no surprise then that the pilot was incredibly successful and HMRC generated a great deal more tax without using a lot of manpower to do so."
According to Grant Thornton, HMRC is now building on its success by sending letters out right across the country. Plenty will be landing on doormats all over the West Midlands.
The letters are not issued at random so those with overseas assets or bank accounts will be in the spotlight.
Investing in property abroad is very popular and is the explanation for so many people having overseas assets.
Not only is the property over-seas, but the owner is also likely to have an overseas bank account to simplify the management of the property.
However, most people forget or simply do not realise that any income made from renting out the property or interest on money in the bank account is likely to be liable to tax in the UK.
Any profits made when the property is sold may also be liable to tax both in the host country and in the UK.
Heather Taylor said: "Anyone who receives a letter like this from the taxman has to consider how to respond.
"You could ignore it and so run the risk of a time consuming and potentially expensive fully fledged tax investigation. Alternatively, you could informally review things with HMRC. Either way, it is important to remember the inspector could be wrong and you owe no extra tax, if there is no income from the overseas asset and you purchased it from money already fully taxed in the UK.
"Our advice would be to adopt a proactive stance. Get all your assets in order now.
"This includes collecting appropriate bank records, which will normally have to go back several years.
"Adopting this type of open and constructive approach is by far the best way to keep any tax liability to a minimum.
"HMRC is going to look more favourably on people who proactively co-operate than on those it has to chase."