Statement Of Financial Position [Abstract]
| Concept |
As at 2022-04-02 |
As at 2022-04-02 |
As at 2022-04-02 |
As at 2022-04-02 |
As at 2022-04-02 |
As at 2022-04-02 |
As at 2021-04-03 |
As at 2021-04-03 |
As at 2021-04-03 |
As at 2021-04-03 |
As at 2021-04-03 |
As at 2021-04-03 |
As at 2020-03-28 |
As at 2020-03-28 |
As at 2020-03-28 |
As at 2020-03-28 |
As at 2020-03-28 |
As at 2020-03-28 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||
| Property, plant and equipment | — | — | — | — |
190,900,000
GBP
|
— | — |
192,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Goodwill | — | — | — | — |
646,000,000
GBP
|
— | — |
646,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill | — | — | — | — |
293,500,000
GBP
|
— | — |
317,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — | — | — |
23,100,000
GBP
|
— | — |
28,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current assets | — | — | — | — |
2,302,200,000
GBP
|
— | — |
2,118,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | ||||||||||||||||||
| Current inventories | — | — | — | — |
78,100,000
GBP
|
— | — |
68,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Trade and other current receivables | — | — | — | — |
96,500,000
GBP
|
— | — |
83,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — | — | — |
54,300,000
GBP
|
— | — |
4,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current assets | — | — | — | — |
231,300,000
GBP
|
— | — |
156,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Assets | — | — | — | — |
2,533,500,000
GBP
|
— | — |
2,274,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||
| Issued capital | — | — | — | — |
86,300,000
GBP
|
— | — |
85,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Retained earnings | — | — | — | — |
1,076,700,000
GBP
|
— | — |
755,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Share premium | — | — | — | — |
1,500,000
GBP
|
— | — |
600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity |
9,300,000
GBP
|
1,076,700,000
GBP
|
1,500,000
GBP
|
86,300,000
GBP
|
1,506,900,000
GBP
|
351,700,000
GBP
|
351,700,000
GBP
|
1,183,600,000
GBP
|
9,300,000
GBP
|
85,500,000
GBP
|
600,000
GBP
|
755,100,000
GBP
|
9,300,000
GBP
|
351,700,000
GBP
|
1,680,000,000
GBP
|
1,409,400,000
GBP
|
84,800,000
GBP
|
156,600,000
GBP
|
| Liabilities [abstract] | ||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||
| Non-current provisions [abstract] | ||||||||||||||||||
| Non-current provisions | — | — | — | — |
8,300,000
GBP
|
— | — |
8,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — | — | — |
212,900,000
GBP
|
— | — |
85,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — | — | — | — |
767,900,000
GBP
|
— | — |
827,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | ||||||||||||||||||
| Current provisions [abstract] | ||||||||||||||||||
| Current provisions | — | — | — | — |
2,300,000
GBP
|
— | — |
6,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Trade and other current payables | — | — | — | — |
254,000,000
GBP
|
— | — |
249,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities | — | — | — | — |
258,700,000
GBP
|
— | — |
263,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Liabilities | — | — | — | — |
1,026,600,000
GBP
|
— | — |
1,091,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |