Statement Of Comprehensive Income [Abstract]
| Concept |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||
| Profit (loss) |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
25,600,000
GBP
|
25,600,000
GBP
|
–
GBP
|
229,400,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
229,400,000
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 | — | — | — | — |
1,100,000
GBP
|
— | — |
5,700,000
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 | — | — | — | — |
16,100,000
GBP
|
— | — |
47,300,000
GBP
|
— | — | — | — | — | — |
| Other comprehensive income, before tax | — | — | — | — |
17,200,000
GBP
|
— | — |
53,000,000
GBP
|
— | — | — | — | — | — |
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] | ||||||||||||||
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss | — | — | — | — |
300,000
GBP
|
— | — |
1,400,000
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 | — | — | — | — |
4,000,000
GBP
|
— | — |
11,900,000
GBP
|
— | — | — | — | — | — |
| Other comprehensive income |
–
GBP
|
–
GBP
|
–
GBP
|
12,100,000
GBP
|
12,900,000
GBP
|
800,000
GBP
|
–
GBP
|
39,700,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
35,400,000
GBP
|
–
GBP
|
4,300,000
GBP
|
| Comprehensive income |
–
GBP
|
–
GBP
|
–
GBP
|
12,100,000
GBP
|
12,700,000
GBP
|
24,800,000
GBP
|
–
GBP
|
269,100,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
35,400,000
GBP
|
–
GBP
|
233,700,000
GBP
|