XML 154 R117.htm IDEA: XBRL DOCUMENT v3.19.1
Deferred tax - Analysis of Deferred Tax Balances for Financial Reporting Purposes (Detail) - GBP (£)
£ in Millions
Dec. 31, 2018
Dec. 31, 2017
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Deferred tax assets £ 153.0 £ 160.3 [1]
Deferred tax liabilities (479.5) (513.7) [1]
Deferred tax assets (liabilities) (326.5) (353.4)
Deferred tax assets, offset (259.0) (251.5)
Deferred tax liabilities, offset 259.0 251.5
Gross amount before offset [member]    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Deferred tax assets 412.0 411.8
Deferred tax liabilities (738.5) (765.2)
Deferred tax assets (liabilities) £ (326.5) £ (353.4)
[1] Prior year figures have been restated for the impact of the adoption of IFRS 15 Revenue from Contracts with Customers, as described in the accounting policies.