v3.26.1
Property, plant and equipment - Disclosure of analysis of property, plant and equipment (Details) - GBP (£)
£ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance £ 74,091  
Property, plant and equipment, ending balance 81,520 £ 74,091
Cost    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 92,457 87,133
Exchange adjustments (1,100) (1,132)
Additions 10,425 8,981
Disposals (602) (694)
Adjustment for change in discount rate on decommissioning provisions (note 26) (88) 7
Reclassifications 49 (12)
Reclassification to held for sale (note 10)   (1,826)
Property, plant and equipment, ending balance 101,141 92,457
Accumulated depreciation    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance (18,366) (18,226)
Exchange adjustments 220 223
Depreciation charge for the year (1,989) (1,924)
Disposals 554 681
Reclassifications (40) (1)
Reclassification to held for sale (note 10)   881
Property, plant and equipment, ending balance (19,621) (18,366)
Land and buildings    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 3,473  
Property, plant and equipment, ending balance 3,612 3,473
Land and buildings | Cost    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 4,244 4,210
Exchange adjustments (55) (55)
Additions 108 60
Disposals (47) (59)
Adjustment for change in discount rate on decommissioning provisions (note 26) (22) 0
Reclassifications 192 198
Reclassification to held for sale (note 10)   (110)
Property, plant and equipment, ending balance 4,420 4,244
Land and buildings | Accumulated depreciation    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance (771) (758)
Exchange adjustments 12 12
Depreciation charge for the year (96) (93)
Disposals 29 49
Reclassifications 18 (32)
Reclassification to held for sale (note 10)   51
Property, plant and equipment, ending balance (808) (771)
Plant and machinery    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 60,841  
Property, plant and equipment, ending balance 65,296 60,841
Plant and machinery | Cost    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 77,766 74,551
Exchange adjustments (934) (965)
Additions 1,362 1,172
Disposals (363) (387)
Adjustment for change in discount rate on decommissioning provisions (note 26) (66) 7
Reclassifications 5,607 4,583
Reclassification to held for sale (note 10)   (1,195)
Property, plant and equipment, ending balance 83,372 77,766
Plant and machinery | Accumulated depreciation    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance (16,925) (16,730)
Exchange adjustments 197 200
Depreciation charge for the year (1,665) (1,632)
Disposals 361 387
Reclassifications (44) 33
Reclassification to held for sale (note 10)   817
Property, plant and equipment, ending balance (18,076) (16,925)
Assets in the course of construction    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 9,022  
Property, plant and equipment, ending balance 11,752 9,022
Assets in the course of construction | Cost    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 9,073 7,022
Exchange adjustments (91) (91)
Additions 8,696 7,529
Disposals (28) (9)
Adjustment for change in discount rate on decommissioning provisions (note 26) 0 0
Reclassifications (5,834) (4,876)
Reclassification to held for sale (note 10)   (502)
Property, plant and equipment, ending balance 11,816 9,073
Assets in the course of construction | Accumulated depreciation    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance (51) (67)
Exchange adjustments 0 0
Depreciation charge for the year 2 4
Disposals 1 9
Reclassifications (16) 3
Reclassification to held for sale (note 10)   0
Property, plant and equipment, ending balance (64) (51)
Motor vehicles and office equipment    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 755  
Property, plant and equipment, ending balance 860 755
Motor vehicles and office equipment | Cost    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance 1,374 1,350
Exchange adjustments (20) (21)
Additions 259 220
Disposals (164) (239)
Adjustment for change in discount rate on decommissioning provisions (note 26) 0 0
Reclassifications 84 83
Reclassification to held for sale (note 10)   (19)
Property, plant and equipment, ending balance 1,533 1,374
Motor vehicles and office equipment | Accumulated depreciation    
Changes in property, plant and equipment [abstract]    
Property, plant and equipment, beginning balance (619) (671)
Exchange adjustments 11 11
Depreciation charge for the year (230) (203)
Disposals 163 236
Reclassifications 2 (5)
Reclassification to held for sale (note 10)   13
Property, plant and equipment, ending balance £ (673) £ (619)