And anyone who finds themselves under investigation for suspected tax irregularities by HM Revenue & Customs has always had to declare all their assets.
But HMRC is now going a step further, and explicitly including a section on cryptocurrency declarations in its updated 'Statement of Assets' form.
No hiding: HMRC can demand to see details of all assets held, including cryptocurrency
An HMRC spokesperson said: 'The majority of individuals and businesses pay the tax that is due – however there remains a determined minority who refuse to play by the rules.
'We take robust action to make sure that everyone pays the tax due – from individuals operating in the hidden economy through to action against sophisticated organised crime groups, and complex investigations into offshore structures used to hide earnings and other assets.'