Statement Of Comprehensive Income [Abstract]
| Concept |
2021-02-01 to 2022-01-31 |
2021-02-01 to 2022-01-31 |
2021-02-01 to 2022-01-31 |
2021-02-01 to 2022-01-31 |
2021-02-01 to 2022-01-31 |
2021-02-01 to 2022-01-31 |
2021-02-01 to 2022-01-31 |
2020-02-01 to 2021-01-31 |
2020-02-01 to 2021-01-31 |
2020-02-01 to 2021-01-31 |
2020-02-01 to 2021-01-31 |
2020-02-01 to 2021-01-31 |
2020-02-01 to 2021-01-31 |
2020-02-01 to 2021-01-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||
| Profit (loss) | — | — | — |
28,000,000
GBP
|
— | — | — | — | — | — |
67,800,000
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 | — | — | — |
4,800,000
GBP
|
— | — | — | — | — | — |
1,200,000
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 | — | — | — |
2,100,000
GBP
|
— | — | — | — | — | — |
22,300,000
GBP
|
— | — | — |
| Reclassification adjustments on cash flow hedges, before tax | — | — | — |
1,200,000
GBP
|
— | — | — | — | — | — |
2,500,000
GBP
|
— | — | — |
| Other comprehensive income, before tax, cash flow hedges | — | — | — |
900,000
GBP
|
— | — | — | — | — | — |
19,800,000
GBP
|
— | — | — |
| Financial assets measured at fair value through other comprehensive income [abstract] | ||||||||||||||
| Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax | — | — | — |
10,300,000
GBP
|
— | — | — | — | — | — |
3,200,000
GBP
|
— | — | — |
| Reclassification adjustments on financial assets measured at fair value through other comprehensive income, before tax | — | — | — |
100,000
GBP
|
— | — | — | — | — | — |
–
GBP
|
— | — | — |
| Other comprehensive income, before tax, financial assets measured at fair value through other comprehensive income | — | — | — |
10,200,000
GBP
|
— | — | — | — | — | — |
3,200,000
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 | — | — | — |
1,200,000
GBP
|
— | — | — | — | — | — |
200,000
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 | — | — | — |
300,000
GBP
|
— | — | — | — | — | — |
3,500,000
GBP
|
— | — | — |
| Income tax relating to financial assets measured at fair value through other comprehensive income included in other comprehensive income | — | — | — |
2,100,000
GBP
|
— | — | — | — | — | — |
800,000
GBP
|
— | — | — |
| Other comprehensive income | — | — | — |
3,300,000
GBP
|
— | — | — | — | — | — |
17,700,000
GBP
|
— | — | — |
| Comprehensive income |
–
GBP
|
–
GBP
|
1,200,000
GBP
|
31,300,000
GBP
|
–
GBP
|
8,100,000
GBP
|
24,400,000
GBP
|
–
GBP
|
68,800,000
GBP
|
16,300,000
GBP
|
50,100,000
GBP
|
–
GBP
|
2,400,000
GBP
|
–
GBP
|
| Comprehensive income attributable to [abstract] | ||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | — |
31,300,000
GBP
|
— | — | — | — | — | — |
50,100,000
GBP
|
— | — | — |