exemption. The details of the payments are private. The Queen voluntarily paid a sum equivalent to income tax on her private income and income from the Privy Purse (which includes the Duchy of Lancaster) that is not used for official purposes. The Sovereign Grant is exempted. A sum equivalent to capital gains tax is voluntarily paid on any gains from the disposal of private assets made after 5 April 1993. Many of the Sovereign's assets were acquired earlier than this date but payment is only made on the gains made afterwards. Arrangements also exist for a sum in lieu of inheritance tax to be voluntarily paid on some of the Queen's private assets. Property passing from monarch to monarch is exempted, as is property passing from the consort of a former monarch to the current monarch. King Charles III, when he was Prince of Wales, voluntarily paid a sum equivalent to income tax on that part of his income from the Duchy of Cornwall that was in excess of what was needed to meet official expenditure. From 1969 he made voluntary tax payments of 50% of the profits, but this reduced to 25% in 1981 when he married Lady Diana Spencer. These arrangements were replaced by the memorandum in 1993. The income of the Prince of Wales from sources other than the Duchy of Cornwall is subject to tax in the normal way. Lobbying and legal exemptions In November 1973, the Queen's private lawyer successfully lobbied the UK government to change proposed legislation in order to conceal her private wealth from the public. The government subsequently inserted a clause into the law granting itself the power to exempt companies used by “heads of state” from new transparency measures. This hid the Queen's private shareholdings and investments until 2011. On other occasions the monarch's advisers requested exclusions from proposed laws relating to road safety and land policy that might affect her estates, and pressed for government policy on historic sites to be altered. The Queen was exempted from the 2017 Cultural Property (Armed Conflicts) Act, a law that seeks to prevent the destruction of cultural heritage, such as archaeological sites, works of art and important books, in future wars. This means police are barred from searching the Queen's private estates for stolen or looted artefacts. The Queen's lawyers also lobbied Scottish ministers to change a draft law, the Heat Networks (Scotland)