Inventories - Composition of inventory balances (Details) - GBP (£) £ in Millions	Dec. 31, 2024	Dec. 31, 2023
Inventories
Raw materials and consumables	£ 236	£ 298
Work in progress	26	20
Finished goods	928	1,090
Total	£ 1,190	£ 1,408

No definition available.

Name:	ifrs-full_ClassesOfInventoriesAbstract
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

A classification of current inventory representing the amount of current raw materials and current production supplies. [Refer: Current production supplies; Current raw materials]

+ References

+ Details

Name:	ifrs-full_CurrentRawMaterialsAndCurrentProductionSupplies
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A classification of current inventory representing the amount of goods that have completed the production process and are held for sale in the ordinary course of business. [Refer: Inventories]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 2
-IssueDate 2024-01-01
-Paragraph 37
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=2&code=ifrs-tx-2024-en-r&anchor=para_37&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 78
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_78_c&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_FinishedGoods
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of current inventories. [Refer: Inventories]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 2
-IssueDate 2024-01-01
-Paragraph 36
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=2&code=ifrs-tx-2024-en-r&anchor=para_36_b&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 54
-Subparagraph g
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_54_g&doctype=Standard
-URIDate 2024-03-27

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 68
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_68&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_Inventories
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A classification of current inventory representing the amount of assets currently in production, which require further processes to be converted into finished goods or services. [Refer: Current finished goods; Inventories]

+ References

+ Details

Name:	ifrs-full_WorkInProgress
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant