Oil Taxation Act 1975 Schedule 2 paragraph 12B

Assessments to tax and determinations of loss, etc.

Paragraph 12B sets out the extended time limits within which HMRC may raise or amend petroleum revenue tax assessments where a participator has brought about a loss of tax through carelessness, deliberate behaviour, or failure to notify a tax avoidance scheme promoter reference number.

• Where a participator (or someone acting on their behalf) carelessly causes an underpayment of tax, an overstated loss, or a missing assessment, HMRC may raise or amend an assessment up to 6 years after the end of the relevant chargeable period.
• Where the loss of tax was brought about deliberately, or where the participator failed to notify HMRC of a promoter reference number for a tax avoidance arrangement as required, the time limit is extended to 20 years after the end of the relevant chargeable period.
• If the participator carried on a trade or business in partnership during the chargeable period in question, HMRC may also assess any of the participator's partners in respect of the profits of that trade or business.
• When calculating the tax due under such an assessment, HMRC must give effect to any relief or allowance the person would have been entitled to had they made a valid claim — but only if the person assessed requests this.