If someone is asked to work from home – even for 1 day – they can lawfully claim tax relief on fuel bills. So if like many many people who are normally in the office you are now being asked to work at home and are suffering with cold &/or higher heating bills it is possible you can claim either:

• Tax relief on £6 a week – eg £1.20 per week (£62.40 for the year) if you’re a 20% basic tax payer (no evidence required), or
• Tax relief on the exact extra cost that you’ve incurred above the weekly amount (evidence required)

Martin Lewis explains it here: https://blog.moneysavingexpert.com/2020/04/martin-lewis–working-from-home-due-to-coronavirus–claim-p6-wk-/

And for the HMRC page, it’s https://www.gov.uk/tax-relief-for-employees/working-at-home