Statement Of Changes In Equity [Abstract]
| Concept |
As at 2024-12-28 |
2023-12-31 to 2024-12-28 |
2023-12-31 to 2024-12-28 |
As at 2024-12-28 |
2023-12-31 to 2024-12-28 |
As at 2024-12-28 |
As at 2024-12-28 |
2023-12-31 to 2024-12-28 |
As at 2024-12-28 |
2023-12-31 to 2024-12-28 |
2023-12-31 to 2024-12-28 |
2023-12-31 to 2024-12-28 |
2023-01-01 to 2023-12-30 |
2023-01-01 to 2023-12-30 |
2023-01-01 to 2023-12-30 |
As at 2023-12-30 |
As at 2023-12-30 |
2023-01-01 to 2023-12-30 |
As at 2023-12-30 |
2023-01-01 to 2023-12-30 |
2023-01-01 to 2023-12-30 |
As at 2023-12-30 |
2023-01-01 to 2023-12-30 |
As at 2023-12-30 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||||||||
| Equity |
400,000
GBP
|
— | — |
543,000,000
GBP
|
— |
570,500,000
GBP
|
2,000,000
GBP
|
— |
25,100,000
GBP
|
— | — | — | — | — | — |
503,400,000
GBP
|
25,100,000
GBP
|
— |
2 .0
GBP
|
— | — |
530,900,000
GBP
|
— |
400,000
GBP
|
446,000,000
GBP
|
23,100,000
GBP
|
400,000
GBP
|
420,500,000
GBP
|
2 .0
GBP
|
| Changes in equity [abstract] | |||||||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||||||
| Profit (loss) | — |
–
GBP
|
–
GBP
|
— |
153,400,000
GBP
|
— | — |
153,400,000
GBP
|
— |
–
GBP
|
12,400,000
GBP
|
14 1.0
GBP
|
15,800,000
GBP
|
126,700,000
GBP
|
–
GBP
|
— | — |
–
GBP
|
— |
142,500,000
GBP
|
142,500,000
GBP
|
— |
–
GBP
|
— | — | — | — | — | — |
| Other comprehensive income | — |
–
GBP
|
–
GBP
|
— |
11,000,000
GBP
|
— | — |
11,000,000
GBP
|
— |
–
GBP
|
— | — | — | — |
–
GBP
|
— | — |
–
GBP
|
— |
400,000
GBP
|
400,000
GBP
|
— |
–
GBP
|
— | — | — | — | — | — |
| Comprehensive income | — |
–
GBP
|
–
GBP
|
— |
142,400,000
GBP
|
— | — |
142,400,000
GBP
|
— |
–
GBP
|
— | — | — | — |
–
GBP
|
— | — |
–
GBP
|
— |
142,900,000
GBP
|
142,900,000
GBP
|
— |
–
GBP
|
— | — | — | — | — | — |
| Issue of equity | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
–
GBP
|
— | — |
2 .0
GBP
|
— |
–
GBP
|
2 .0
GBP
|
— |
–
GBP
|
— | — | — | — | — | — |
| Dividends recognised as distributions to owners | — |
–
GBP
|
–
GBP
|
— |
106,800,000
GBP
|
— | — |
106,800,000
GBP
|
— |
–
GBP
|
— | — | — | — |
–
GBP
|
— | — |
–
GBP
|
— |
60,800,000
GBP
|
60,800,000
GBP
|
— |
–
GBP
|
— | — | — | — | — | — |
| Increase (decrease) through share-based payment transactions, equity | — |
–
GBP
|
–
GBP
|
— |
4,500,000
GBP
|
— | — |
4,500,000
GBP
|
— |
–
GBP
|
— | — | — | — |
–
GBP
|
— | — |
–
GBP
|
— |
4,600,000
GBP
|
4,600,000
GBP
|
— |
–
GBP
|
— | — | — | — | — | — |