This may be helpful.
...companies in the UK must include certain regulatory information on their company websites and in their email footers from 1st January 2007 or they will breach the Companies Act in the UK and risk a fine.
Every company should list its company registration number, place of registration and registered office address on its website as a result of an update to the legislation of 1985. The information, which must be in legible characters, should also appear on order forms and in
emails. Such information is already required on ‘business letters’ but the duty is being extended to websites, order forms and electronic documents.
Excerpted from:
Accessibility 101 > Accessible Web Design Blog » Is your Company Website in breach of UK laws - specifically the 2007 Companies Act?