This Order specifies the conditions that a project carried out in an oil field must satisfy in order for that oil field to be an “additionally-developed oil field” (“ADOF”) for the purposes of Chapter 7 of Part 8 of the Corporation Tax Act 2010 (c. 4) (“CTA 2010”). An oil field that is an ADOF qualifies for a “field allowance”. The effect of a field allowance is to reduce the extent to which profits are subject to the supplementary charge. In addition, this Order inserts a new section 356A into the CTA 2010. This new section prescribes the method by which the total field allowance for an ADOF is to be calculated. This Order also makes a number of consequential amendments to Chapter 7 of Part 8 of, and Schedule 4 to, the CTA 2010; firstly, to specify the time at which a company having an interest in an ADOF is entitled to the field allowance, and secondly, to amend section 349A(1) of the CTA 2010 so that the language of that provision more accurately reflects the way in which approval for the carrying out of projects is granted.