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 |
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
|
56,800,000
GBP
|
–
GBP
|
–
GBP
|
56,800,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
453,400,000
GBP
|
453,400,000
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
|
313,600,000
GBP
|
–
GBP
|
–
GBP
|
313,600,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
82,700,000
GBP
|
82,700,000
GBP
|
| Other comprehensive income, before tax, change in fair value of financial liability attributable to change in credit risk of liability |
–
GBP
|
4,100,000
GBP
|
–
GBP
|
–
GBP
|
4,100,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
43,300,000
GBP
|
43,300,000
GBP
|
| Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract] | ||||||||||
| Cash flow hedges [abstract] | ||||||||||
| Other comprehensive income, before tax, cash flow hedges |
–
GBP
|
–
GBP
|
106,700,000
GBP
|
–
GBP
|
106,700,000
GBP
|
9,300,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
9,300,000
GBP
|
| Cost of hedging [abstract] | ||||||||||
| Change in value of foreign currency basis spreads [abstract] | ||||||||||
| Other comprehensive income, before tax, change in value of foreign currency basis spreads | — | — | — | — |
–
GBP
|
12,700,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
12,700,000
GBP
|
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] | ||||||||||
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss | — | — | — | — |
109,400,000
GBP
|
— | — | — | — |
36,600,000
GBP
|
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract] | ||||||||||
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss | — | — | — | — |
26,800,000
GBP
|
— | — | — | — |
1,800,000
GBP
|
| Comprehensive income |
–
GBP
|
143,300,000
GBP
|
79,900,000
GBP
|
–
GBP
|
223,200,000
GBP
|
400,000
GBP
|
–
GBP
|
–
GBP
|
361,600,000
GBP
|
361,200,000
GBP
|