Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2022-12-31 |
As at 2021-12-31 |
|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||
| Property, plant and equipment [abstract] | ||
| Property, plant and equipment |
74,800,000
GBP
|
66,600,000
GBP
|
| Investment property [abstract] | ||
| Investment property |
800,000
GBP
|
800,000
GBP
|
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract] | ||
| Investments in joint ventures reported in separate financial statements |
84,000,000
GBP
|
94,100,000
GBP
|
| Trade and other current receivables [abstract] | ||
| Trade and other current receivables |
353,000,000
GBP
|
328,300,000
GBP
|
| Current prepayments and current accrued income including current contract assets [abstract] | ||
| Current accrued income including current contract assets [abstract] | ||
| Current contract assets |
294,600,000
GBP
|
232,600,000
GBP
|
| Categories of current financial assets [abstract] | ||
| Current loans and receivables |
400,000
GBP
|
1,500,000
GBP
|
| Classes of current inventories [abstract] | ||
| Current inventories |
333,900,000
GBP
|
288,500,000
GBP
|
| Classes of current inventories, alternative [abstract] | ||
| Cash and cash equivalents [abstract] | ||
| Cash and cash equivalents |
431,700,000
GBP
|
468,600,000
GBP
|
| Borrowings [abstract] | ||
| Non-current portion of non-current borrowings |
–
GBP
|
400,000
GBP
|
| Current borrowings and current portion of non-current borrowings [abstract] | ||
| Current borrowings |
77,100,000
GBP
|
110,200,000
GBP
|
| Non-current portion of non-current borrowings, by type [abstract] | ||
| Trade and other non-current payables [abstract] | ||
| Trade and other non-current payables |
37,300,000
GBP
|
32,600,000
GBP
|
| Trade and other current payables [abstract] | ||
| Current accruals and current deferred income including current contract liabilities [abstract] | ||
| Current deferred income including current contract liabilities [abstract] | ||
| Current contract liabilities [abstract] | ||
| Current contract liabilities |
74,200,000
GBP
|
78,500,000
GBP
|
| Trade and other current payables |
963,200,000
GBP
|
891,400,000
GBP
|
| Miscellaneous non-current liabilities [abstract] | ||
| Non-current net defined benefit liability |
200,000
GBP
|
200,000
GBP
|
| Issued capital [abstract] | ||
| Issued capital |
2,400,000
GBP
|
2,300,000
GBP
|
| Retained earnings [abstract] | ||
| Retained earnings |
436,800,000
GBP
|
427,100,000
GBP
|
| Accumulated other comprehensive income [abstract] | ||
| Reserve of exchange differences on translation |
1,300,000
GBP
|
800,000
GBP
|
| Reserve of cash flow hedges |
800,000
GBP
|
800,000
GBP
|
| Miscellaneous equity [abstract] | ||
| Capital redemption reserve |
600,000
GBP
|
600,000
GBP
|
| Net assets (liabilities) [abstract] | ||
| Assets |
1,794,400,000
GBP
|
1,707,600,000
GBP
|
| Liabilities |
1,298,200,000
GBP
|
1,233,400,000
GBP
|
| Assets (liabilities) |
496,200,000
GBP
|
474,200,000
GBP
|
| Net current assets (liabilities) [abstract] | ||
| Current assets |
1,413,600,000
GBP
|
1,324,200,000
GBP
|
| Current liabilities |
1,191,200,000
GBP
|
1,126,900,000
GBP
|
| Current assets (liabilities) |
222,400,000
GBP
|
197,300,000
GBP
|
| Assets less current liabilities [abstract] |