The borderline between taxes and purchases of services from government is
defined according to the same criteria as those used in the case of payments made
by enterprises: if the licences are being granted automatically on payment of
the amounts due, their payment is treated as taxes. But if the government uses
the issue of licences to organise some proper regulatory function (such as
checking the competence, or qualifications, of the person concerned), the payments
made should be treated as purchases of services from government rather than
payments of taxes, unless the payments are clearly out of all proportion to the cost
of providing the services.