'It is to be observed that in all the cases which have previously come before the court, the question has been whether a single transaction for a single price should be properly apportioned into two or more supplies. What the 20 contracting parties have joined together, the commissioners may put asunder, but what the contracting parties have themselves separated; I do not think that the commissioners can join together.' [104] The second case was Nell Gwynn House Maintenance Fund 25 Trustees v Customs and Excise Comrs[1999] STC 79 ,[1999] 1 WLR 174 which concerned the liability to VAT of the trustees of a maintenance fund in respect of maintenance payments made by lessees. In relation to one issue it was accepted that if the maintenance had been undertaken by the lessor the supply of the 30 relevant services would be exempt from VAT by virtue of the exemption applicable to the leasing or letting of immovable property. But it was contended that the position was different where, as in the Nell Gwynn case, the maintenance was undertaken by trustees who were separate from the lessor. Lord Slynn, with whom 35 the rest of their lordships agreed, rejected an argument based upon Henriksen Case 178/88[1990] STC 768 . He said ([1999] SRC 79 at 92,[1999] 1 WLR 174 at 185): '