S.L. 601.1 · General Financial Regulations (S.L. 601.1)
S.L. 601.1 Art. 70Restrictions on expenditure.
Except with the specific authority of the Minister no accounting officer may make any purchase, contract, agreement or arrangement involving expenditure from a head -
(a) in excess of the sum provided on the appropriate subhead; and
(b) on any materials, works or services not included in the estimates.