Statement Of Comprehensive Income [Abstract]
| Concept |
2023-12-31 to 2024-12-28 |
2023-12-31 to 2024-12-28 |
2023-12-31 to 2024-12-28 |
2023-12-31 to 2024-12-28 |
2023-12-31 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 |
2023-01-01 to 2023-12-30 |
2023-01-01 to 2023-12-30 |
2023-01-01 to 2023-12-30 |
2023-01-01 to 2023-12-30 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||
| Profit (loss) |
–
GBP
|
–
GBP
|
153,400,000
GBP
|
–
GBP
|
153,400,000
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 [abstract] | ||||||||||||||
| Components of other comprehensive income that will not be reclassified to profit or loss, before tax [abstract] | ||||||||||||||
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans | — | — |
11,900,000
GBP
|
— | — | — | — | — | — | — | — | — |
–
GBP
|
— |
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] | ||||||||||||||
| Income tax relating to remeasurements of defined benefit plans included in other comprehensive income | — | — |
900,000
GBP
|
— | — | — | — | — | — | — | — | — |
400,000
GBP
|
— |
| Other comprehensive income |
–
GBP
|
–
GBP
|
11,000,000
GBP
|
–
GBP
|
11,000,000
GBP
|
— | — | — | — |
–
GBP
|
–
GBP
|
400,000
GBP
|
400,000
GBP
|
–
GBP
|
| Comprehensive income |
–
GBP
|
–
GBP
|
142,400,000
GBP
|
–
GBP
|
142,400,000
GBP
|
— | — | — | — |
–
GBP
|
–
GBP
|
142,900,000
GBP
|
142,900,000
GBP
|
–
GBP
|