15 Assets classified as held for sale

During the year, the group entered into an agreement which will involve the disposal of its non-household water and wastewater retail business, principally comprising billing and customer service activities, into a new joint venture with Severn Trent PLC. As at 31 March 2016, completion of the disposal was expected within 12 months, subject to clearance from the Competition and Markets Authority, and so £18.3 million of intangible assets have been classified as held for sale. These assets have subsequently been impaired by £2.7 million during the year to give a carrying value of £15.6 million, which ensures that the assets are valued at fair value less cost to sell in accordance with IFRS 5 'Non-current Assets Held for Sale and Discontinued Operations'. See note 25 for events occurring after 31 March 2016.