v3.25.4
Financial Risk Management - Summary of Sensitivity of Carrying Value of Financial Instruments to Fluctuations in Interest Rates and Exchange Rates (Detail) - GBP (£)
£ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of financial instruments carrying value [line items]    
Financial assets £ 1,217 £ 1,515
Cash and cash equivalents 333 543
Derivative financial instruments 13 (7)
Financial liabilities (1,782) (1,825)
Investment in finance lease receivable 66 83
Total financial instruments (480) (310)
Impact of 1% increase in interest rates 2 4
Impact of 1% decrease in interest rates (2) (4)
Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates (15) (17)
Impact of 10% weakening in exchange rates 14 25
Investments in unlisted securities [member]    
Disclosure of financial instruments carrying value [line items]    
Financial assets 125 141
Impact of 1% increase in interest rates 0 0
Impact of 1% decrease in interest rates 0 0
Investments in unlisted securities [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates (8) (10)
Impact of 10% weakening in exchange rates 10 12
Other receivable [member]    
Disclosure of financial instruments carrying value [line items]    
Financial assets 16 12
Other receivables 16 12
Impact of 1% increase in interest rates 0 0
Impact of 1% decrease in interest rates 0 0
Other receivable [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates (1) (1)
Impact of 10% weakening in exchange rates 2 1
Cash and cash equivalents [member]    
Disclosure of financial instruments carrying value [line items]    
Financial assets 333 543
Cash and cash equivalents 333 543
Impact of 1% increase in interest rates 0 0
Impact of 1% decrease in interest rates 0 0
Cash and cash equivalents [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates (23) (32)
Impact of 10% weakening in exchange rates 27 40
Derivative financial instruments [member]    
Disclosure of financial instruments carrying value [line items]    
Financial assets 16 51
Derivative financial instruments 13 (7)
Impact of 1% increase in interest rates 2 4
Impact of 1% decrease in interest rates (2) (4)
Derivative financial instruments [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates 41 22
Impact of 10% weakening in exchange rates (56) (24)
Bonds [member]    
Disclosure of financial instruments carrying value [line items]    
Financial liabilities (706) (955)
Impact of 1% increase in interest rates 0 0
Impact of 1% decrease in interest rates 0 0
Bonds [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates 0 23
Impact of 10% weakening in exchange rates 0 (28)
Other borrowings [member]    
Disclosure of financial instruments carrying value [line items]    
Other borrowings (775) (517)
Impact of 1% increase in interest rates 0 0
Impact of 1% decrease in interest rates 0 0
Other borrowings [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates 16 19
Impact of 10% weakening in exchange rates (19) (23)
Investment in finance lease receivable [member]    
Disclosure of financial instruments carrying value [line items]    
Financial assets 66 83
Investment in finance lease receivable 66 83
Impact of 1% increase in interest rates 0 0
Impact of 1% decrease in interest rates 0 0
Investment in finance lease receivable [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates (6) (8)
Impact of 10% weakening in exchange rates 7 9
Deferred and contingent consideration [member]    
Disclosure of financial instruments carrying value [line items]    
Financial liabilities (17) (22)
Deferred and contingent consideration (17) (22)
Impact of 1% increase in interest rates 0 0
Impact of 1% decrease in interest rates 0 0
Deferred and contingent consideration [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates 2 2
Impact of 10% weakening in exchange rates (2) (2)
Other net financial assets [member]    
Disclosure of financial instruments carrying value [line items]    
Other net financial assets 465 412
Impact of 1% increase in interest rates 0 0
Impact of 1% decrease in interest rates 0 0
Other net financial assets [member] | Sterling [member]    
Disclosure of financial instruments carrying value [line items]    
Impact of 10% strengthening in exchange rates (36) (32)
Impact of 10% weakening in exchange rates £ 45 £ 40