Statement Of Comprehensive Income [Abstract]
| Concept |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||
| Profit (loss) |
–
GBP
|
87,200,000
GBP
|
296,500,000
GBP
|
209,300,000
GBP
|
–
GBP
|
–
GBP
|
87,200,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
219,200,000
GBP
|
7,000,000
GBP
|
212,200,000
GBP
|
212,200,000
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
|
188,500,000
GBP
|
— | — |
–
GBP
|
–
GBP
|
188,500,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
162,000,000
GBP
|
162,000,000
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
|
— | — |
54,600,000
GBP
|
–
GBP
|
54,600,000
GBP
|
33,500,000
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
33,500,000
GBP
|
| Reclassification adjustments on cash flow hedges, before tax |
–
GBP
|
–
GBP
|
— | — |
6,800,000
GBP
|
–
GBP
|
6,800,000
GBP
|
8,200,000
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
8,200,000
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
|
47,100,000
GBP
|
— | — |
–
GBP
|
–
GBP
|
47,100,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
30,800,000
GBP
|
30,800,000
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
|
— | — |
13,000,000
GBP
|
–
GBP
|
13,000,000
GBP
|
6,300,000
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
6,300,000
GBP
|
| Other comprehensive income | — | — | — | — | — | — |
196,500,000
GBP
|
— | — | — | — | — | — |
97,400,000
GBP
|
| Comprehensive income |
–
GBP
|
62,600,000
GBP
|
— | — |
46,700,000
GBP
|
–
GBP
|
109,300,000
GBP
|
33,800,000
GBP
|
–
GBP
|
–
GBP
|
— | — |
81,000,000
GBP
|
114,800,000
GBP
|