Taxes Management Act 1970 section 36

Loss of tax brought about carelessly or deliberately etc.

Section 36 sets out the extended time limits within which HMRC may raise assessments for income tax or capital gains tax where there has been a loss of tax due to carelessness, deliberate behaviour, or failure to comply with certain notification and disclosure obligations.

• Where a loss of tax is brought about carelessly, HMRC may raise an assessment up to 6 years after the end of the relevant tax year.
• Where a loss of tax is brought about deliberately, or is attributable to a failure to notify chargeability or to comply with tax avoidance disclosure obligations, the time limit is extended to 20 years.
• Where the person in default was in a partnership, an extended assessment may also be raised on their partners in respect of the partnership profits.
• A person assessed under these provisions may request that any reliefs or allowances they were entitled to for the period in question are taken into account in calculating the tax charged.