XML 163 R149.htm IDEA: XBRL DOCUMENT v3.8.0.1
Inventories - Summary of Current Inventories (Detail) - GBP (£)
£ in Millions
Dec. 31, 2017
Dec. 31, 2016
Classes of current inventories [abstract]    
Raw materials £ 4 £ 5
Work in progress 2 6
Finished goods 142 224
Inventories £ 148 £ 235