The amount of financial liabilities at amortised cost. The amortised cost is the amount at which financial liabilities are measured at initial recognition minus principal repayments, plus or minus the cumulative amortisation using the effective interest method of any difference between that initial amount and the maturity amount. [Refer: Financial liabilities]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 8
-Subparagraph f
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_8_f&doctype=Standard&book=B
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 8
-Subparagraph g
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-01&anchor=para_8_g&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_FinancialLiabilitiesAtAmortisedCost
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Financial liabilities on funding arrangements - Narrative (Details) £ in Thousands, $ in Millions	3 Months Ended
	Apr. 30, 2018 GBP (£)	Apr. 30, 2017 GBP (£)	Apr. 30, 2018 USD ($)	Apr. 30, 2018 GBP (£)	Jan. 31, 2018 GBP (£)	Jan. 31, 2017 GBP (£)
Disclosure of financial liabilities [line items]
Financial liabilities at amortised cost				£ 3,231	£ 3,090	£ 5,919
Increase in fair value of financial liabilities for funding arrangements	£ 100	£ 200
Specified Regulatory Milestones
Disclosure of financial liabilities [line items]
Financial liabilities at amortised cost \| $			$ 2.5