The provision regarding the maximum rate of royalty on crude oil to which my hon. Friend refers is contained in the clause entitled "Provision for Periodical Revision of Royalties" which is on page 16 of the Model Clauses scheduled to the Petroleum (Production) Regulations, 1935. A clause of this kind incorporated in any oil-mining licence granted under the Regulations will represent a firm contract as between the Board of Trade and the licensee. If at any future time new or modified regulations are made, their provisions will, of course, apply to any new licences granted after the date such regulations come into force, but will not affect the terms of any licence previously granted.