An officer of Revenue and Customs may enquire into an interest restriction return submitted by a reporting company if the officer gives notice to the company of the officer's intention to do so (“notice of enquiry”).

The general rule is that an interest restriction return which has been the subject of one notice of enquiry may not be the subject of another.

If a return (“the previous return”) is superseded by an interest restriction return submitted under paragraph 8 (“the revised return”), notice of enquiry may be given in relation to the revised return even though notice of enquiry has been given in relation to the previous return.

But see paragraph 43(5) for a limitation in certain circumstances on the scope of an enquiry into an interest restriction return submitted under paragraph 8.

The power to give notice of enquiry into an interest restriction return for a period of account of a worldwide group does not restrict the power to give notice of enquiry into a company tax return of a company that is a member of the group at any time in that period.

Accordingly, an amendment of the company's company tax return may be required as a result of an enquiry into the interest restriction return even though a closure notice has been given in respect of an enquiry into that company tax return.

But see paragraph 43(2) for a limitation on the scope of an enquiry into an interest restriction return so far as affecting amounts in a company tax return.