| Mar 31,
2018 | Mar 31,
2019 | Mar 31,
2020 | Mar 31,
2021 | Mar 31,
2022 | Mar 31,
2023 | Mar 31,
2024 | Mar 31,
2025 |
|---|
| Profit (loss) from operating activities | 3,493 | 2,870 | 2,780 | 2,895 | 4,371 | 4,879 | 4,475 | 4,934 |
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| Gain on sale of investments | - | - | - | - | 228 | 846 | - | 188 |
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| Other fair value movements | - | - | - | -22 | -65 | 21 | -16 | 66 |
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| Depreciation, amortisation and impairment | 1,530 | 1,588 | 1,640 | 1,672 | 1,830 | 1,984 | 2,061 | 2,479 |
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| Share-based payments | 16 | 27 | 19 | 27 | 38 | 48 | 37 | 37 |
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| Changes in working capital | -118 | -40 | -394 | -296 | 223 | -547 | 147 | -40 |
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| Changes in provisions | -206 | -110 | 198 | -195 | 149 | -155 | 840 | -287 |
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| Changes in pensions and other post-retirement benefit obligations | -239 | -123 | -117 | -55 | -84 | -46 | 31 | -90 |
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| Cash generated from operations – continuing operations | 4,702 | 4,464 | 4,914 | 4,618 | 5,788 | 6,432 | 7,281 | 6,991 |
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| Tax paid | -8 | 75 | 199 | 157 | 298 | 89 | 342 | 183 |
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| Net cash inflow from operating activities – continuing operations | 4,710 | 4,389 | 4,715 | 4,461 | 5,490 | 6,343 | 6,939 | 6,808 |
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| Net cash inflow from operating activities – discontinued operations | -207 | -71 | -97 | - | 782 | 555 | - | - |
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| Purchases of intangible assets | 173 | 306 | 317 | 426 | 446 | 567 | 549 | 526 |
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| Purchases of property, plant and equipment | 3,738 | 3,635 | 4,583 | 4,362 | 5,098 | 6,325 | 6,904 | 8,780 |
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| Disposals of property, plant and equipment | 10 | 38 | 68 | 8 | 26 | 87 | 52 | 26 |
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| Investments in joint ventures and associates | 129 | 143 | 82 | 81 | 265 | 443 | 332 | 396 |
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| Dividends received from joint ventures, associates and other investments | - | - | - | - | - | 190 | 176 | 126 |
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| UK Electricity System Operator | - | - | - | - | - | - | - | 577 |
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| UK Gas Transmission business | - | - | - | - | - | - | 681 | 686 |
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| Cash flows from losing control of subsidiaries or other businesses, classified as investing activities | -20 | - | - | - | - | - | - | - |
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| Disposal of financial and other investments | 134 | 18 | 63 | 66 | 215 | 116 | 102 | 85 |
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| Acquisition of financial investments | 2 | 89 | 108 | 99 | 197 | 95 | 81 | 122 |
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| National Grid Renewables and Emerald Energy Venture LLC | - | - | - | - | - | - | 19 | - |
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| Contributions to National Grid Renewables and Emerald Energy Venture LLC | - | - | 139 | 26 | - | - | - | - |
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| Net movements in short-term financial investments | 5,953 | 822 | 7 | -436 | - | 586 | -1,141 | -2,606 |
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| Interest received | 57 | 68 | 73 | 16 | 40 | 65 | 148 | 332 |
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| Cash inflows on derivatives | - | - | - | 225 | 17 | - | 123 | 11 |
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| Cash outflows on derivatives | - | - | - | 81 | 122 | 362 | - | 6 |
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| Insurance claim from loss of property, plant and equipment | - | - | - | - | - | - | 143 | - |
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| Net cash flow (used in)/from investing activities – continuing operations | 2,237 | -3,190 | -3,201 | -5,116 | -13,885 | 804 | -7,601 | -10,593 |
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| Cash flows from (used in) investing activities, discontinued operations | - | 156 | 6 | - | -125 | -564 | 102 | 22 |
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| Proceeds of Rights Issue | - | - | - | - | - | - | - | 7,001 |
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| Transaction fees related to Rights Issue | - | - | - | - | - | - | - | 162 |
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| Proceeds from issue of treasury shares | 33 | 17 | 16 | 16 | 33 | 16 | 20 | 18 |
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| Transactions in own shares | - | - | - | - | - | 1 | -4 | -7 |
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| Proceeds received from loans | 1,941 | 2,932 | 4,218 | 5,645 | 12,347 | 11,908 | 5,563 | 3,237 |
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| Repayment of loans | 2,156 | 1,969 | 3,253 | 1,663 | 1,261 | 15,260 | 1,701 | 2,861 |
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| Payments of lease liabilities | - | - | 121 | 112 | 117 | 155 | 118 | 130 |
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| Net movements in short-term borrowings | - | - | -424 | -759 | -11 | -511 | 544 | 925 |
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| Cash inflows on derivatives | - | - | - | 58 | 20 | 190 | 86 | 62 |
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| Cash outflows on derivatives | - | - | - | 185 | 114 | 118 | 58 | 106 |
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| Interest paid | 853 | 914 | 957 | 835 | 1,053 | 1,430 | 1,627 | 1,920 |
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| Dividends paid to shareholders | 4,487 | 1,160 | 892 | 1,413 | 922 | 1,607 | 1,718 | 1,529 |
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| Net cash flow from/(used in) financing activities – continuing operations | -7,316 | -1,364 | -1,606 | 750 | 8,919 | -6,966 | 987 | 4,528 |
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| Net cash flow used in financing activities – discontinued operations | -231 | - | - | - | -1,150 | -207 | - | - |
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| Net increase/(decrease) in cash and cash equivalents | - | - | - | - | 31 | - | 427 | 765 |
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| Reclassification to held for sale | - | - | - | - | - | 9 | -30 | -123 |
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| Exchange movements | -3 | 3 | 4 | -7 | 5 | 7 | -1 | -23 |
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