Stashing money in a Swiss bank account is not against the law. As long as you declare all the income and gains from your overseas investments and bank accounts on your UK tax return, there is no problem at all. Unfortunately some individuals have taken advantage of the Swiss laws which permit banks to keep their customers' details completely confidential, even from tax authorities, and did not declared the income on their tax returns. 

To remedy this non-disclosure (AKA tax evasion), the UK Government has reached a unique tax deal with Switzerland. From 2013, investment income from Swiss bank accounts held by UK residents will be subject to a withholding tax of 48%, and gains made on those investments will be subject to withholding tax of 27%. These withholding taxes will NOT apply if the bank account holder authorises the bank to disclose all details of the income to HMRC, and pays any associated taxes in the UK. 

To settle past tax liabilities, all existing funds held by UK taxpayers in Switzerland will be subject to a one-off deduction of between 19% and 34%. This deduction will only apply to amounts in bank accounts open at 31 December 2010, which remain open at 31 May 2013. However, if the bank account holder has instructed the bank to disclose details of the account to HMRC, the one-off deduction will not apply, but HMRC will follow-up all disclosures made.

If you hold a Swiss bank account, now would be a very good time to discuss this with a tax professional.

Neil Harries TI tax editor and director at Cardiff Accountants Harries Watkins Jones.

The author does not guarantee the accuracy of any information provided in this article and recommends that you do not take any action, whatsoever, based on the information provided. By the fullest extent permitted by law, the author does not accept any responsibility for any actions you may or may not take based on information contained in this article. This article contains general information and is not a substitute for specific independent professional advice. In addition it is emphasised that much of the information provided in this article is time sensitive and information contained within it may be out of date.