Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2022-03-31 |
As at 2021-03-31 |
As at 2020-03-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
4 385
GBP
|
4 052
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets and goodwill |
1 126
GBP
|
1 061
GBP
|
— |
| Investments accounted for using equity method [abstract] | |||
| Investments accounted for using equity method |
165,000,000
GBP
|
171,000,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current net defined benefit asset |
1,000,000
GBP
|
110,000,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
834,000,000
GBP
|
826,000,000
GBP
|
— |
| Categories of current financial assets [abstract] | |||
| Current loans and receivables |
6,000,000
GBP
|
2,000,000
GBP
|
— |
| Classes of current inventories [abstract] | |||
| Current inventories |
97,000,000
GBP
|
109,000,000
GBP
|
— |
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
534,000,000
GBP
|
294,000,000
GBP
|
329,000,000
GBP
|
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings |
1 688
GBP
|
1 686
GBP
|
— |
| Current borrowings and current portion of non-current borrowings [abstract] | |||
| Current borrowings |
115,000,000
GBP
|
91,000,000
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
586,000,000
GBP
|
49 8
GBP
|
— |
| Miscellaneous non-current liabilities [abstract] | |||
| Non-current net defined benefit liability |
119,000,000
GBP
|
127,000,000
GBP
|
— |
| Non-current derivative financial liabilities |
128,000,000
GBP
|
124,000,000
GBP
|
— |
| Miscellaneous current liabilities [abstract] | |||
| Current net defined benefit liability |
20,000,000
GBP
|
14,000,000
GBP
|
— |
| Current derivative financial liabilities |
1,000,000
GBP
|
2,000,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
74,000,000
GBP
|
74,000,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
4 597
GBP
|
4 523
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
7 207
GBP
|
6 672
GBP
|
— |
| Liabilities |
3 961
GBP
|
3 705
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
1 474
GBP
|
1 232
GBP
|
— |
| Current liabilities |
823,000,000
GBP
|
684,000,000
GBP
|
— |
| Assets less current liabilities [abstract] |