hus in the NZZ writes about options for British tax evaders to come clean about hidden financial assets abroad.
UK residents with Swiss assets who do not want their identity to be disclosed to the British authorities can pay taxes on their asset holdings to the Swiss authorities instead; the Swiss will (partly) hand them over to London. The relevant treaty between the UK and Switzerland was put into effect in 2013.
UK residents often prefer an alternative option, though, namely to “legalise” their world wide asset holdings using a treaty between Liechtenstein and the UK. According to that treaty, assets fully declared before the end of 2016 trigger a penalty of about 10% to 20% of the relevant asset holdings, as compensation for evaded taxes in the past. British tax payers can use this option as long as the fraction of their offshore assets that they invested in Liechtenstein is sufficiently high.