Spires will appear alongside Ben Colburn and Finlay Robinson for the Westbourne Motorsport team with which he raced in Brands Hatch’s opening rounds in April.
The Buckingham racer has attracted sponsorship from DriveTech and also plans to contest the season finale at Brands Hatch a fortnight later.
Spires, aged 27, said: “It’s great finally to get back on the Clio Cup grid, especially at my home circuit and at a very interesting time in the season with the title at stake – a huge thank you to DriveTech for supporting me and I am sure they will benefit from being in front of a large crowd and also the live ITV4 cameras.
“I feel we showed some promising pace at Brands back in the spring so hopefully we can pick up where we left off at Silverstone.
“Friday’s two test sessions will be important in terms of seat time for me but also setting up the car to my liking ahead of qualifying on Saturday.”
Colin Paterson, Head of Marketing at DriveTech, commented: “We are delighted to be sponsoring Anton for the up-coming Silverstone and Brands Hatch events.
"DriveTech focuses heavily on road safety but I think we can all agree that there is a time and place for speeding and competitive driving; round the track is definitely it – good luck Anton!”