Statement Of Comprehensive Income [Abstract]
| Concept |
2024-04-01 to 2025-03-31 |
2024-04-01 to 2025-03-31 |
2024-04-01 to 2025-03-31 |
2024-04-01 to 2025-03-31 |
2024-04-01 to 2025-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||
| Profit (loss) |
–
GBP
|
–
GBP
|
229,400,000
GBP
|
–
GBP
|
229,400,000
GBP
|
–
GBP
|
140,200,000
GBP
|
140,200,000
GBP
|
–
GBP
|
–
GBP
|
| Other comprehensive income [abstract] | ||||||||||
| Components of other comprehensive income that will not be reclassified to profit or loss, before tax [abstract] | ||||||||||
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans |
–
GBP
|
–
GBP
|
37,800,000
GBP
|
–
GBP
|
37,800,000
GBP
|
–
GBP
|
16,400,000
GBP
|
16,400,000
GBP
|
–
GBP
|
–
GBP
|
| Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract] | ||||||||||
| Cash flow hedges [abstract] | ||||||||||
| Gains (losses) on cash flow hedges, before tax |
–
GBP
|
–
GBP
|
3,700,000
GBP
|
3,700,000
GBP
|
–
GBP
|
6,100,000
GBP
|
–
GBP
|
6,100,000
GBP
|
–
GBP
|
–
GBP
|
| Reclassification adjustments on cash flow hedges, before tax |
–
GBP
|
–
GBP
|
12,600,000
GBP
|
12,600,000
GBP
|
–
GBP
|
18,200,000
GBP
|
–
GBP
|
18,200,000
GBP
|
–
GBP
|
–
GBP
|
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] | ||||||||||
| Income tax relating to remeasurements of defined benefit plans included in other comprehensive income |
–
GBP
|
–
GBP
|
9,400,000
GBP
|
–
GBP
|
9,400,000
GBP
|
–
GBP
|
4,200,000
GBP
|
4,200,000
GBP
|
–
GBP
|
–
GBP
|
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract] | ||||||||||
| Income tax relating to cash flow hedges included in other comprehensive income |
–
GBP
|
–
GBP
|
1,000,000
GBP
|
1,000,000
GBP
|
–
GBP
|
1,500,000
GBP
|
–
GBP
|
1,500,000
GBP
|
–
GBP
|
–
GBP
|
| Other comprehensive income | — | — |
35,100,000
GBP
|
— | — | — | — |
21,200,000
GBP
|
— | — |
| Comprehensive income |
–
GBP
|
–
GBP
|
264,500,000
GBP
|
6,700,000
GBP
|
257,800,000
GBP
|
9,000,000
GBP
|
152,400,000
GBP
|
161,400,000
GBP
|
–
GBP
|
–
GBP
|