Analysis Of Income And Expense [Abstract]
| Concept |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Analysis of income and expense [abstract] | ||||||||||||||||
| Material income and expense [abstract] | ||||||||||||||||
| Investment income | — | — | — | — |
—
GBP
|
5 3 .7
GBP
|
5 3 .7
GBP
|
— | — | — |
8 9.0
GBP
|
89. 0
GBP
|
—
GBP
|
— | — | — |
| Interest expense | — | — | — | — |
—
GBP
|
12 . 3
GBP
|
12 . 3
GBP
|
— | — | — |
22. 7
GBP
|
22. 7
GBP
|
—
GBP
|
— | — | — |
| Operating expense | — | — | — | — |
3 .9
GBP
|
1 6 7. 4
GBP
|
17 1. 3
GBP
|
— | — | — |
2 10 . 0
GBP
|
19 1. 3
GBP
|
18 . 7
GBP
|
— | — | — |
| Sales and marketing expense | — | — | — | — |
—
GBP
|
4 6 . 9
GBP
|
4 6. 9
GBP
|
— | — | — |
4 6. 8
GBP
|
4 6 . 8
GBP
|
—
GBP
|
— | — | — |
| Fee and commission income (expense) [abstract] | ||||||||||||||||
| Fee and commission income [abstract] | ||||||||||||||||
| Other fee and commission income | — | — | — | — |
—
GBP
|
3,500,000
GBP
|
3,500,000
GBP
|
— | — | — |
3,000,000
GBP
|
3,000,000
GBP
|
—
GBP
|
— | — | — |
| Fee and commission income | — | — | — | — |
—
GBP
|
16 5 . 5
GBP
|
16 5 . 5
GBP
|
— | — | — |
15 5 . 7
GBP
|
15 5 . 7
GBP
|
—
GBP
|
— | — | — |
| Expenses by nature [abstract] | ||||||||||||||||
| Classes of employee benefits expense [abstract] | ||||||||||||||||
| Employee benefits expense | — | — | — | — |
—
GBP
|
7 7. 7
GBP
|
7 7.7
GBP
|
— | — | — |
8 5 . 3
GBP
|
8 1. 3
GBP
|
4 .0
GBP
|
— | — | — |
| Depreciation, amortisation and impairment loss (reversal of impairment loss) recognised in profit or loss [abstract] | ||||||||||||||||
| Depreciation, amortisation and impairment loss (reversal of impairment loss) recognised in profit or loss | — | — | — | — |
3 .9
GBP
|
13 . 9
GBP
|
1 7. 8
GBP
|
— | — | — |
3 0 .9
GBP
|
1 7. 2
GBP
|
13 .7
GBP
|
— | — | — |
| Other expenses, by nature | — | — | — | — |
—
GBP
|
29. 0
GBP
|
29. 0
GBP
|
— | — | — |
4 0 . 8
GBP
|
39. 8
GBP
|
1. 0
GBP
|
— | — | — |
| Miscellaneous other comprehensive income [abstract] | ||||||||||||||||
| Other comprehensive income, net of tax, exchange differences on translation of foreign operations and hedges of net investments in foreign operations [abstract] | ||||||||||||||||
| Other comprehensive income, net of tax, exchange differences on translation of foreign operations |
—
GBP
|
—
GBP
|
—
GBP
|
1. 4
GBP
|
—
GBP
|
1,400,000
GBP
|
1. 4
GBP
|
—
GBP
|
—
GBP
|
—
GBP
|
1,700,000
GBP
|
1. 7
GBP
|
—
GBP
|
1,700,000
GBP
|
—
GBP
|
—
GBP
|
| Share of profit (loss) of associates and joint ventures accounted for using equity method [abstract] | ||||||||||||||||
| Share of profit (loss) of associates accounted for using equity method | — | — | — | — |
—
GBP
|
900,000
GBP
|
0 .9
GBP
|
— | — | — |
0 .8
GBP
|
0 .8
GBP
|
—
GBP
|
— | — | — |
| Comprehensive income, continuing and discontinued operations [abstract] | ||||||||||||||||
| Comprehensive income |
—
GBP
|
—
GBP
|
—
GBP
|
1,400,000
GBP
|
3 .9
GBP
|
66,500,000
GBP
|
62 .6
GBP
|
61,200,000
GBP
|
10 8 .3
GBP
|
—
GBP
|
10 6 . 6
GBP
|
8 7. 9
GBP
|
18 .7
GBP
|
1,700,000
GBP
|
—
GBP
|
—
GBP
|
| Comprehensive income attributable to owners of parent, continuing and discontinued operations [abstract] | ||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | — | — |
3 .9
GBP
|
66,500,000
GBP
|
62 .6
GBP
|
— | — | — |
10 6 . 6
GBP
|
8 7. 9
GBP
|
18 .7
GBP
|
— | — | — |