The Scot, who has been out of the BTCC for three seasons, whisked his Team Dynamics Honda Civic Type R around a gargantuan 0.194 seconds clear of his closest opposition on the four-cornered circuit with a couple of late runs.
Out of five fliers, three of Shedden’s laps were quicker than anyone else’s best, and the other two were within 0.006s of being faster than the rest.
The surprise performance of the test was the brand-new Team Hard Cupra Leon of Jack Goff, who ended up second overall.
Goff headed the morning times, which were generally slightly slower, and jumped up the order again towards the end of the afternoon, although admitted that the team is unsure of where it stands with the likelihood that the established frontrunners were running considerable levels of success ballast.
Michael Crees headed much of the afternoon session with what at the time was the quickest lap of the day, but the BTC Racing Honda driver didn’t go out on track in the late stages and dropped to third.
Like Shedden and Goff, Tom Ingram was another late improver as he continued to make a good start to life with the Excelr8 Motorsport Hyundai i30N and ended the day in fourth.
That was enough to head BTCC returnee Jason Plato, the two-time champion and all-time wins record holder in the series claiming fifth with the Power Maxed Racing Vauxhall Astra after taking a year out in 2020.
Last year’s runner-up and champion, Colin Turkington and Ash Sutton, were second and third respectively in the morning, but failed to improve in the afternoon and ended up sixth and seventh.
Turkington and the West Surrey Racing BMW 330i M Sport team spent the day focusing on running with relatively high levels of ballast, while Sutton was happy to continue working through a test programme with the Laser Tools Racing/BMR Infiniti Q50, after the COVID lockdown scuppered much of the squad’s pre-2020 development programme.
Adam Morgan claimed eighth on the day for Ciceley Motorsport as it builds up to its first season with WSR-built BMWs, while Daniel Lloyd completed a good day for the PMR Vauxhall squad by going ninth.
Daniel Rowbottom, in the second Dynamics Honda, completed the top 10 after recovering from an engine failure in the morning session, to narrowly deny the BTC Honda of Josh Cook.
Expected frontrunners not to feature in the top 10 were Rory Butcher, 17th overall in the Speedworks Motorsport Toyota Corolla, and Jake Hill, who missed most of the afternoon running due to a technical problem on his Motorbase-run MB Motorsport Ford Focus.