Statement Of Changes In Net Assets Available For Benefits [Abstract]
| Concept |
2021-12-27 to 2022-12-25 |
2021-12-27 to 2022-12-25 |
2021-12-27 to 2022-12-25 |
2020-12-28 to 2021-12-26 |
2020-12-28 to 2021-12-26 |
2020-12-28 to 2021-12-26 |
|---|---|---|---|---|---|---|
| Statement of changes in net assets available for benefits [abstract] | ||||||
| Reconciliation of changes in net assets available for benefits [abstract] | ||||||
| Changes in net assets available for benefits [abstract] | ||||||
| Other income |
—
GBP
|
1,000,000
GBP
|
1,000,000
GBP
|
2 .1
GBP
|
—
GBP
|
2 .1
GBP
|
| Administrative expenses |
—
GBP
|
131. 8
GBP
|
131. 8
GBP
|
129,900,000
GBP
|
4,500,000
GBP
|
125. 4
GBP
|
| Other expense, by function |
—
GBP
|
—
GBP
|
—
GBP
|
300,000
GBP
|
300,000
GBP
|
—
GBP
|
| Tax expense (income) |
—
GBP
|
17 .3
GBP
|
17 .3
GBP
|
1 9.0
GBP
|
1,500,000
GBP
|
20 .5
GBP
|