Post balance sheet events (Details) £ in Millions	Jul. 27, 2017 GBP (£)
Professional indemnity insurance policies agreement
Post balance sheet events
Pre-tax payment receivable on claim settlement	£ 272

The amount of income arising from insurance contracts. [Refer: Types of insurance contracts [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 4
-IssueDate 2017-01-01
-Paragraph 37
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=4&date=2017-03-01&anchor=para_37_b&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_IncomeArisingFromInsuranceContracts
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration