XML 194 R176.htm IDEA: XBRL DOCUMENT v3.22.1
Share-Based Payments - Summary of Shares Granted under Restricted Share Arrangements (Detail) - Restricted shares [member]
Unit_pure in Thousands
12 Months Ended
Dec. 31, 2021
GBP (£)
Dec. 31, 2020
GBP (£)
Long-term incentive plan [member]    
Disclosure of terms and conditions of share-based payment arrangement [line items]    
Number of shares 6,394 5,598
Weighted average fair value £ 7.27 £ 4.94
Management incentive plan [member]    
Disclosure of terms and conditions of share-based payment arrangement [line items]    
Number of shares 630 696
Weighted average fair value £ 7.71 £ 5.29