2019-20 UK Tax Deadline Wednesday, 20 January 2021 8:30 am 9:30 am 08:30 09:30 ProACT Partnership Expatriate Advice 59-60 Thames Street Windsor, England, SL4 1TX United Kingdom (map) Google Calendar ICS Submit your 2019-20 UK tax return and pay tax online by 31st December 2021.If you need help submitting your return, contact us.