Er .. not strictly true. The state of affairs of some companies can be such that they can go into a Creditors' Voluntary Liquidation straight away without having the process of either Adminstration or Receivership first.
If a substantial, non-secured creditor, feels that the company is trading fraudulently (i.e. it does not have the working capital to meet its liabilities), that creditor can apply to the courts for a Creditors' Voluntary Liquidation. If other creditors come forth (as they undoubtedly would after a posting in the London Gazette) and support the application, the courts can impose the liquidation.
There is also the Members' Voluntary Liquidation where the shareholders of a profitable company can just decide to commit suicide.
Cheers
Whirls