v3.26.1
Assets held for sale and discontinued operations - Narrative (Details)
£ in Millions, $ in Millions
1 Months Ended 2 Months Ended 8 Months Ended 12 Months Ended
May 29, 2025
GBP (£)
May 29, 2025
USD ($)
Jul. 31, 2024
GBP (£)
May 29, 2025
GBP (£)
Nov. 28, 2025
GBP (£)
Mar. 31, 2026
GBP (£)
Mar. 31, 2025
GBP (£)
Mar. 31, 2024
GBP (£)
Disclosure of subsidiaries [line items]                
Profit after tax           £ 3,243 £ 2,905 £ 2,291
GasT TopCo Limited                
Disclosure of subsidiaries [line items]                
Consideration paid (received)     £ (686)          
Gains (losses) on disposals of assets held for sale     £ 25          
National Grid Renewables                
Disclosure of subsidiaries [line items]                
Profit after tax       £ (14)     (60) (65)
National Grid Renewables | Disposal groups classified as held for sale                
Disclosure of subsidiaries [line items]                
Consideration paid (received) £ (1,531) $ (2,061)            
Grain LNG                
Disclosure of subsidiaries [line items]                
Profit after tax         £ 89   £ 120 £ 114
Provision for post closing capital expenditure           £ 124    
UK Gas Transmission business                
Disclosure of subsidiaries [line items]                
Proportion of ownership interest disposed     20.00%