If you are a Ltd Co you are technically an employee of yourself, and as such need to have EL insurance.
However, in the latest issue from Federation of Small Businesses there is an article on this very subject.
QUOTE
A consultation seeking views on whether the requirement for the smallest companies to have employers' compulsory liability insuranceshould be removed, has been launched by the Dept for Work and Pensions. Some 300,000 companies where the owner is the sole employee would be affected by the removal of the requirement, which would bring them into line with similar unincorporated bisinesses.
The DWP's initial view following a review of ELCI is that one-man companies should be exempted. The consultation paper is at (it gave the wrong address as this link is obviously out of date, the consultation closed on June 22. After a bit of searching I got the following . . .)
http://www.dwp.gov.uk/publications/dwp/2003/elci/dwp_employers_review04-12-2003.pdfYou can contact Public enquiries on 020 7712 2171 for more information.