For the best information on Thruxton see Geoff Brown's post here: https://www.lotus7.club/news/thruxton-historic-12th-13th-june-2021
I have an update from the organisers, for those of you who are wondering if you can commit under the present circumstances.
Thruxton Circuit deal with ticketing and have a ‘Buy with Confidence’ message - Should the circuit be unable to admit spectators ticket buyers will have the option to transfer their tickets or request a full refund.
Event information and latest news can be found here https://thruxtonracing.co.uk/racing/historic
Under the EVENT INFO tab on that page you will find Thruxton Circuit Covid-19 information page ‘WHAT WE'RE DOING TO KEEP GUESTS SAFE AT THRUXTON’
Arrangements are subject to Government and Motorsport UK regulations in force at the time and things are looking good for the event to continue with spectators as planned. Visitor numbers will be capped in line with government restrictions in place until 21st June.