Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2021-12-31 |
As at 2020-12-31 |
As at 2020-01-01 |
As at 2019-01-01 |
|---|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||||
| Property, plant and equipment [abstract] | ||||
| Property, plant and equipment |
4,7 42
GBP
|
5,091,000
GBP
|
— | — |
| Intangible assets and goodwill [abstract] | ||||
| Intangible assets other than goodwill [abstract] | ||||
| Intangible assets other than goodwill |
127,809,000
GBP
|
143,585,000
GBP
|
— | — |
| Goodwill |
547,509,000
GBP
|
54 7,509
GBP
|
— | — |
| Miscellaneous non-current assets [abstract] | ||||
| Non-current investments other than investments accounted for using equity method |
175,064,000
GBP
|
145,153,000
GBP
|
— | — |
| Trade and other current receivables [abstract] | ||||
| Trade and other current receivables |
241,420,000
GBP
|
225,022,000
GBP
|
— | — |
| Trade and other receivables [abstract] | ||||
| Trade and other receivables |
454,000
GBP
|
1,544,000
GBP
|
— | — |
| Cash and cash equivalents [abstract] | ||||
| Cash and cash equivalents |
398,714,000
GBP
|
340,988,000
GBP
|
340,988,000
GBP
|
361,962,000
GBP
|
| Miscellaneous assets [abstract] | ||||
| Net defined benefit asset |
45,318,000
GBP
|
9,077,000
GBP
|
— | — |
| Classes of other provisions [abstract] | ||||
| Other provisions [abstract] | ||||
| Other non-current provisions |
30,928,000
GBP
|
33,786,000
GBP
|
— | — |
| Other current provisions |
8,455,000
GBP
|
6,615,000
GBP
|
— | — |
| Trade and other current payables [abstract] | ||||
| Trade and other current payables |
966,127,000
GBP
|
894,503,000
GBP
|
— | — |
| Trade and other payables [abstract] | ||||
| Trade and other payables |
211,296,000
GBP
|
139,316,000
GBP
|
— | — |
| Issued capital [abstract] | ||||
| Issued capital |
111,154,000
GBP
|
111,127,000
GBP
|
— | — |
| Retained earnings [abstract] | ||||
| Retained earnings |
1,094,833,000
GBP
|
899,785,000
GBP
|
— | — |
| Miscellaneous equity [abstract] | ||||
| Merger reserve |
823,513,000
GBP
|
823,513,000
GBP
|
— | — |
| Net assets (liabilities) [abstract] | ||||
| Assets |
3,843,249,000
GBP
|
3,632,194,000
GBP
|
— | — |
| Liabilities |
1,452,668,000
GBP
|
1,437,112,000
GBP
|
— | — |
| Net current assets (liabilities) [abstract] | ||||
| Current assets |
2,602,289,000
GBP
|
2,416,881,000
GBP
|
— | — |
| Current liabilities |
988,904,000
GBP
|
966,422,000
GBP
|
— | — |
| Assets less current liabilities [abstract] |