From HMRC website
http://www.hmrc.gov.uk/ct/managing/director-loan.htm
If you're a company director or 'participator' and take money out of your company that's not a salary or a dividend - over and above any money you've put in - you're classed as having received the benefit of a director's loan.
If your director's loan account is overdrawn, your company must pay tax on any amount you've not repaid by nine months after the end of your Corporation Tax accounting period.
This guide explains what a director's loan is and the Corporation Tax implications for your company. It tells you if or when you need to inform HM Revenue & Customs (HMRC) that a director's loan exists and explains what entries you need to include in your Company Tax Return to account for any tax that's due.
It also mentions possible Income Tax implications of directors' loans for you and your company.