Where the market value of an asset on a particular date or the apportionment of any amount or value is a material question in an appeal any person whose liability to capital gains tax for any period may be affected by that market value or by the manner in which that amount or value is apportioned may apply under this Regulation to be joined as a party in the appeal.

The inspector shall send a copy of the application to the appellant and to any other party to the appeal.

If the application is received by the inspector not later than thirty days before the date fixed for the hearing of the appeal (or of the question), or if when he receives the application no date has been fixed, he shall, if he is satisfied that it is proper to join the applicant as a party in the appeal, join him as a third party and give notice of the joinder to the appellant and any other party to the appeal.

If the application is received by the inspector later than thirty days before the date fixed for the hearing of the appeal (or of the question) but before it has been determined, or if he is not satisfied that it is proper to join the applicant as a party in the appeal, he shall refer the application to the Commissioners before whom the appeal is brought, and those Commissioners may in their discretion allow or refuse the application.

The Commissioners before whom the appeal is brought may on the application of a third party transfer the appeal to the General Commissioners for the division in which the applicant ordinarily resides at the date of the application, or to the Special Commissioners:

Provided that an appeal shall not be so transferred unless the Commissioners to whom the application is made are satisfied that the balance of convenience to the parties is in favour of the transfer.

At the hearing and on the determination of the appeal or of any question in the appeal a third party shall, so far as relates to the question in which he is interested, have the same rights as an appellant, including any right to require the statement of a case for the opinion of any Court.

On the hearing of the appeal or of any question in the appeal a third party shall not (unless the appellant consents) be entitled to be present except during such part of the hearing as relates to a question in which he is interested, and the Commissioners shall if necessary hear any such question separately from the rest of the appeal.

A person entitled under section 26(5) of the Finance Act 1965 (proceedings consequent on death) to be a party to an appeal shall, if he wishes to be made a party, apply to be joined under this Regulation.