UK: the Unregistered Companies Regulations 2009

The Unregistered Companies Regulations 2009 were laid before Parliament on 8 September and come into force on 1 October 2009. The Regulations have been published on OPSI: see here (html) and here (pdf). In the accompanying explanatory memorandum the purpose of the Regulations is explained: to apply specified provisions of the Companies Act (1985) and Companies Act (2006) to unregistered companies (those not incorporated under any of the Companies Acts but through, e.g., a private Act of Parliament or Royal Charter). The explanatory memorandum explains:

The exact number of unregistered companies is not known. It is believed that most have been formed by Royal Charter: over 900 such companies have been formed since the 13th Century but many are now defunct. About 400 are still actively within the purview of the Privy Council. Of these, many were not formed for the purpose of carrying on a business that has for its object the acquisition of gain by the body or its individual members. Fewer than 50 unregistered companies have, in recent years, filed documents with Companies House as required by the 1985 Act. (By way of contrast, there are nearly 2.5 million active companies formed under the Companies Acts.)".