The Companies Act 2006 finally came into full force on 1 October 2009. Watch out for:

Definitions - “subsidiary”, “holding company” and “wholly-owned subsidiary” now defined in s1159 Companies Act 2006; “subsidiary undertaking” and “parent undertaking” now defined in s1162 Companies Act 2006.

Authorised share capital has been abolished.

All companies now have a short form memorandum of association (minus objects etc).

New companies should be adopting articles based on the new model articles.

More details at: http://www.mayerbrown.com/publications/article.asp?id=6618&nid=6