v3.25.3
Segmental analysis - Schedule of revenue by segment (Details) - GBP (£)
£ in Millions
 6 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Disclosure of operating segments [line items]    
Total revenue from continuing operations £ 7,065 £ 7,961
UK    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 2,702 3,755
US    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 4,363 4,206
UK Electricity Transmission    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 1,406 1,182
UK Electricity Distribution    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 896 1,164
UK Electricity System Operator    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 0 1,012
New England    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 1,493 1,545
New York    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 2,667 2,341
National Grid Ventures    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 581 624
Other    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 22 93
Operating segments    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 7,130 8,103
Operating segments | UK Electricity Transmission    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 1,443 1,274
Operating segments | UK Electricity Distribution    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 901 1,166
Operating segments | UK Electricity System Operator    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 0 1,029
Operating segments | New England    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 1,493 1,545
Operating segments | New York    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 2,667 2,341
Operating segments | National Grid Ventures    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 601 650
Operating segments | Other    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 25 98
Sales between segments    
Disclosure of operating segments [line items]    
Total revenue from continuing operations (65) (142)
Sales between segments | UK Electricity Transmission    
Disclosure of operating segments [line items]    
Total revenue from continuing operations (37) (92)
Sales between segments | UK Electricity Distribution    
Disclosure of operating segments [line items]    
Total revenue from continuing operations (5) (2)
Sales between segments | UK Electricity System Operator    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 0 (17)
Sales between segments | New England    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 0 0
Sales between segments | New York    
Disclosure of operating segments [line items]    
Total revenue from continuing operations 0 0
Sales between segments | National Grid Ventures    
Disclosure of operating segments [line items]    
Total revenue from continuing operations (20) (26)
Sales between segments | Other    
Disclosure of operating segments [line items]    
Total revenue from continuing operations £ (3) £ (5)