Financial instruments and risk management - Credit Risk, Additional Information (Details) - GBP (£) £ in Millions	Dec. 31, 2024	Dec. 31, 2023
Short Term Credit Facility
Disclosure Of Fair Value Measurement Of Liabilities [Line Items]
Maximum exposure to credit risk	£ 1	£ 1
Leaf Supply Arrangements
Disclosure Of Fair Value Measurement Of Liabilities [Line Items]
Maximum exposure to credit risk	£ 52	£ 51

The amount that best represents the maximum exposure to credit risk without taking into account any collateral held or other credit enhancements (for example, netting agreements that do not qualify for offset in accordance with IAS 32). [Refer: Credit risk [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2024-01-01
-Paragraph 35K
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_35K_a&doctype=Standard
-URIDate 2024-03-27

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant