Financial instruments and risk management - Summary of Credit Quality of Financial Assets (Details) - GBP (£) £ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Credit Risk Exposure [Line Items]
Financial assets	£ 301	£ 10,303
Credit Risk
Disclosure Of Credit Risk Exposure [Line Items]
Financial assets	632	29,609
Credit Risk \| Trade Receivables
Disclosure Of Credit Risk Exposure [Line Items]
Financial assets	331	29,306
Credit Risk \| Financial Assets at Amortised Cost - Non-current
Disclosure Of Credit Risk Exposure [Line Items]
Financial assets	£ 301	£ 303

The amount of financial assets at amortised cost. The amortised cost is the amount at which financial assets 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, and adjusted for any impairment. [Refer: Financial assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2021-01-01
-Paragraph 8
-Subparagraph f
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2021-en-r&anchor=para_8_f&doctype=Standard
-URIDate 2021-03-24

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