v3.26.1
Derivative financial instruments (Tables)
 12 Months Ended
Mar. 31, 2026
Disclosure of detailed information about financial instruments [abstract]  
Disclosure of detailed information about derivative financial instruments The fair values of derivatives by category are as follows:
2026
2025
Assets
£m
Liabilities
£m
Total
£m
Assets
£m
Liabilities
£m
Total
£m
Current
215
(268)
(53)
113
(381)
(268)
Non-current
623
(750)
(127)
369
(821)
(452)
838
(1,018)
(180)
482
(1,202)
(720)
Financing derivatives
717
(950)
(233)
375
(1,138)
(763)
Commodity contract
derivatives
121
(68)
53
107
(64)
43
838
(1,018)
(180)
482
(1,202)
(720)
The fair values of financing derivatives by type are as follows:
2026
2025
Assets
£m
Liabilities
£m
Total
£m
Assets
£m
Liabilities
£m
Total
£m
Interest rate swaps
129
(216)
(87)
98
(196)
(98)
Cross-currency interest rate
swaps
448
(528)
(80)
193
(766)
(573)
Foreign exchange forward
contracts¹
114
(120)
(6)
53
(81)
(28)
Inflation-linked swaps
26
(86)
(60)
31
(95)
(64)
717
(950)
(233)
375
(1,138)
(763)
1.Included within the foreign exchange forward contracts balance are £19 million (2025: £45 million) of derivative liabilities in relation to the
hedging of capital expenditureThe notional contract amounts of financing derivatives by type are as follows:
2026
2025
£m
£m
Interest rate swaps
(7,113)
(7,763)
Cross-currency interest rate swaps
(16,413)
(16,019)
Foreign exchange forward contracts
(11,508)
(7,761)
Inflation-linked swaps
(2,970)
(3,190)
(38,004)
(34,733)
The fair values of commodity contract derivatives by type are as follows:
2026
2025
Assets
£m
Liabilities
£m
Total
£m
Assets
£m
Liabilities
£m
Total
£m
Commodity purchase contracts
accounted for as derivative contracts
Forward purchases of gas
—
—
—
3
(7)
(4)
Gas options
3
(3)
—
—
—
—
Derivative financial instruments
linked to commodity prices
Electricity capacity
7
(10)
(3)
2
(17)
(15)
Electricity swaps
110
(44)
66
74
(38)
36
Electricity options
—
—
—
1
(1)
—
Gas swaps
—
(8)
(8)
15
(1)
14
Gas options
1
(3)
(2)
12
—
12
121
(68)
53
107
(64)
43
The notional quantities of commodity contract derivatives by type are as follows:
2026
2025
Forward purchases of gas1
13m Dth
74m Dth
Electricity capacity
4 TWh
5 TWh
Electricity swaps
15,514 GWh
14,040 GWh
Electricity options
241 GWh
334 GWh
Gas swaps
28m Dth
30m Dth
Gas options
139m Dth
89m Dth
1.Forward gas purchases have terms up to one month (2025: three years). The contractual obligations under these contracts are £21 million
(2025: £46 million)
Disclosure of maturity analysis for derivative financial liabilities The maturity profile of financing derivatives is as follows:
2026
2025
Assets
£m
Liabilities
£m
Total
£m
Assets
£m
Liabilities
£m
Total
£m
Current
Less than 1 year
123
(237)
(114)
19
(355)
(336)
123
(237)
(114)
19
(355)
(336)
Non-current
In 1 to 2 years
88
(86)
2
46
(61)
(15)
In 2 to 3 years
69
(45)
24
41
(77)
(36)
In 3 to 4 years
34
(17)
17
47
(73)
(26)
In 4 to 5 years
51
(8)
43
6
(25)
(19)
More than 5 years
352
(557)
(205)
216
(547)
(331)
594
(713)
(119)
356
(783)
(427)
717
(950)
(233)
375
(1,138)
(763)
The maturity profile of commodity contract derivatives is as follows:
2026
2025
Assets
£m
Liabilities
£m
Total
£m
Assets
£m
Liabilities
£m
Total
£m
Current
Less than one year
92
(31)
61
94
(26)
68
92
(31)
61
94
(26)
68
Non-current
In 1 to 2 years
27
(24)
3
12
(20)
(8)
In 2 to 3 years
1
(11)
(10)
1
(12)
(11)
In 3 to 4 years
1
(2)
(1)
—
(2)
(2)
In 4 to 5 years
—
—
—
—
(2)
(2)
More than 5 years
—
—
—
—
(2)
(2)
29
(37)
(8)
13
(38)
(25)
121
(68)
53
107
(64)
43