Analysis Of Income And Expense [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 |
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 |
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Analysis of income and expense [abstract] | ||||||||||||||||||||||
| Revenue [abstract] | ||||||||||||||||||||||
| Revenue | — | — | — | — | — | — | — | — | — |
3 233
GBP
|
— | — | — | — | — |
2 995
GBP
|
— | — | — | — | — | — |
| Material income and expense [abstract] | ||||||||||||||||||||||
| Write-downs (reversals of write-downs) of property, plant and equipment [abstract] | ||||||||||||||||||||||
| Impairment loss recognised in profit or loss, property, plant and equipment | — | — | — | — | — | — | — | — | — |
7,000,000
GBP
|
— | — | — | — | — |
3,000,000
GBP
|
— | — | — | — | — | — |
| Expenses by nature [abstract] | ||||||||||||||||||||||
| Raw materials and consumables used | — | — | — | — | — | — | — | — | — |
770,000,000
GBP
|
— | — | — | — | — |
719,000,000
GBP
|
— | — | — | — | — | — |
| Services expense | — | — | — | — | — | — | — | — | — |
169,000,000
GBP
|
— | — | — | — | — |
147,000,000
GBP
|
— | — | — | — | — | — |
| Classes of employee benefits expense [abstract] | ||||||||||||||||||||||
| Employee benefits expense | — | — | — | — | — | — | — | — | — |
1 522
GBP
|
— | — | — | — | — |
1 448
GBP
|
— | — | — | — | — | — |
| Depreciation, amortisation and impairment loss (reversal of impairment loss) recognised in profit or loss [abstract] | ||||||||||||||||||||||
| Depreciation and amortisation expense [abstract] | ||||||||||||||||||||||
| Depreciation and amortisation expense | — | — | — | — | — | — | — | — | — |
228,000,000
GBP
|
— | — | — | — | — |
217,000,000
GBP
|
— | — | — | — | — | — |
| Disclosure of attribution of expenses by nature to their function [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Disclosure of attribution of expenses by nature to their function [abstract] | ||||||||||||||||||||||
| Disclosure of attribution of expenses by nature to their function [line items] | ||||||||||||||||||||||
| Share of profit (loss) of associates and joint ventures accounted for using equity method [abstract] | ||||||||||||||||||||||
| Share of profit (loss) of associates and joint ventures accounted for using equity method | — | — | — | — | — | — | — | — | — |
1,000,000
GBP
|
— | — | — | — | — |
70,000,000
GBP
|
— | — | — | — | — | — |
| Share of other comprehensive income of associates and joint ventures accounted for using equity method, net of tax [abstract] | ||||||||||||||||||||||
| Share of other comprehensive income of associates and joint ventures accounted for using equity method that will be reclassified to profit or loss, net of tax | — | — | — | — | — | — | — | — | — |
1,000,000
GBP
|
— | — | — | — | — |
–
GBP
|
— | — | — | — | — | — |
| Income tax relating to components of other comprehensive income [abstract] | ||||||||||||||||||||||
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss | — | — | — | — | — | — | — | — | — |
16,000,000
GBP
|
— | — | — | — | — |
26,000,000
GBP
|
— | — | — | — | — | — |
| Comprehensive income, continuing and discontinued operations [abstract] | ||||||||||||||||||||||
| Comprehensive income |
258,000,000
GBP
|
–
GBP
|
30,000,000
GBP
|
1 74
GBP
|
74,000,000
GBP
|
4,000,000
GBP
|
–
GBP
|
6,000,000
GBP
|
–
GBP
|
288,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
237,000,000
GBP
|
–
GBP
|
29,000,000
GBP
|
–
GBP
|
–
GBP
|
192,000,000
GBP
|
–
GBP
|
16,000,000
GBP
|
45,000,000
GBP
|
| Comprehensive income attributable to owners of parent, continuing and discontinued operations [abstract] | ||||||||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | — | — | — | — | — | — | — |
258,000,000
GBP
|
— | — | — | — | — |
45,000,000
GBP
|
— | — | — | — | — | — |
| Comprehensive income attributable to non-controlling interests, continuing and discontinued operations [abstract] | ||||||||||||||||||||||
| Comprehensive income, attributable to non-controlling interests | — | — | — | — | — | — | — | — | — |
30,000,000
GBP
|
— | — | — | — | — |
16,000,000
GBP
|
— | — | — | — | — | — |