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HMRC internal manual

Oil Taxation Manual

PRT: administration: chargeable periods


PRT is charged by reference to chargeable periods. There are two chargeable periods each year, each of six months duration, ending on 30 June or 31 December respectively.

First and subsequent chargeable periods, OTA75\S1(3)

The first chargeable period for any field, for all the initial participators in that field, is defined in OTA75\S1(3)(a) as the period ending at the end of the ‘critical half year’ (including an unlimited time prior to the beginning of that year).

Each subsequent half-year ending on 30 June and 31 December is a chargeable period in accordance with OTA75\S1(3)(b).

Critical half year, OTA75\S1(4)

The ‘critical half year’ for any field is defined as the first half year at the end of which the total amount of oil ever won (including oil in transit) and saved from the field exceeds 1,000 metric tonnes.

For the purpose of calculating the equivalent of this limit where production from a field includes natural gas, one metric tonne is to be taken as equal to 1,100 cubic metres of gas at a temperature of 15°C and a pressure of one atmosphere.