Employers Liability Insurance

As I understand it, every employer is required by law to have employer's liability insurance. In the case of a one-person company, I can think of no circumstances in which any claim would arise since the owner/director would be claining against him/herself. Why would anybody want to make a gift to an insurance company by paying a premium on such a policy ? In such a situation, does this law apply, and if so, is it enforceable ? What might be the penalties for not having it ?
Stephen Henley