A letter to HMRC I think. VAT legislation provides that tips paid to staff under the "tronc" system are exempt from VAT. This amount must be paid into a tronc bank account, which is administered by a staff member designated as "tronc master". A PAYE account must be opened in his name with HMRC.

Tips on card takings can be verified by the daily Z roll summary, but not so with cash takings.