Shares in subsidiary undertakings
£000
Cost
At 1 July 2016425,443
Additions34,290
At 30 June 2017459,733
Impairment
At 30 June 201612,244
Charge for the period
At 30 June 201712,244
Net book value
At 30 June 2017447,489
At 30 June 2016413,199

A list of subsidiary undertakings is given in note (xii). During the year, the Company invested in Dechra Investments Limited and Dechra Finance Ireland DAC, both wholly owned subsidiaries.