Statement Of Comprehensive Income [Abstract]
| Concept |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
2020-10-01 to 2021-09-30 |
2020-10-01 to 2021-09-30 |
2020-10-01 to 2021-09-30 |
2020-10-01 to 2021-09-30 |
2020-10-01 to 2021-09-30 |
2020-10-01 to 2021-09-30 |
2020-10-01 to 2021-09-30 |
2020-10-01 to 2021-09-30 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||||
| Profit (loss) |
313,600,000
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
313,600,000
GBP
|
-
GBP
|
164,500,000
GBP
|
-
GBP
|
-
GBP
|
164,500,000
GBP
|
-
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 |
15,300,000
GBP
|
— | — | — | — | — | — | — | — |
8,200,000
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
|
— | — | — | — | — | — | — | — |
3,000,000
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 |
3,700,000
GBP
|
— | — | — | — | — | — | — | — |
900,000
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
|
— | — | — | — | — | — | — | — |
500,000
GBP
|
— | — | — | — | — | — |
| Other comprehensive income |
11,600,000
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
11,600,000
GBP
|
-
GBP
|
4,800,000
GBP
|
-
GBP
|
-
GBP
|
7,300,000
GBP
|
-
GBP
|
2,500,000
GBP
|
-
GBP
|
| Comprehensive income |
325,200,000
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
-
GBP
|
325,200,000
GBP
|
-
GBP
|
169,300,000
GBP
|
-
GBP
|
-
GBP
|
171,800,000
GBP
|
-
GBP
|
2,500,000
GBP
|
-
GBP
|