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A valid biometric residence permit proves that you are a British resident and you would be eligible to enter UK despite the travel ban.
From 1 January onwards people with residence rights include: holders of Indefinite Leave to Remain; holders of existing leave to enter or remain (i.e those with biometric Residence permits) or an entry clearance/visa that grants such leave e.g. students, workers, etc (excluding visit visas); holders of EU Settlement Scheme (“EUSS”) leave; those who have rights of entry under the Withdrawal Agreements (including returning residents with a right of residence under the EEA Regulations and EEA frontier workers); family members of EEA nationals with rights under the Withdrawal Agreement.
https://www.gov.uk/foreign-travel-advice/argentina (e.g. for Argentina, but the definitions are the same for all countries)
You would be required to self-isolate for 10 days and follow all public health instructions applicable to you.