Director liability: directors of private companies can be held jointly and severally responsible for unrecoverable tax, interest or penalties. Where tax, interest or penalty for supplies by a private company cannot be recovered, every person who was a director during the relevant period is jointly and severally liable unless he proves non-recovery cannot be attributed to any gross neglect, misfeasance or breach of duty; if the private company is converted into a public company and such amounts remain unrecovered before conversion, the joint and several liability does not apply to former private-company directors, but personal penalties on directors remain unaffected.