Five former British Touring Car champions received penalties after a controversial weekend at Croft.
Gordon Shedden had moved to within five points of championship leader Colin Turkington with a third in race three, but has been given a four-second penalty for gaining an unfair advantage after contact with Mat Jackson.
The penalty moves the Honda Civic Tourer driver to fourth, behind the Motorbase Ford Focus, and therefore loses two championship points.
Race three winner Andrew Jordan has also received a 10-place grid penalty after contact with Fabrizio Giovanardi's Motorbase Ford on the opening lap.
His Eurotech Honda team has appealed the decision, which will be investigated at the Snetterton round in August.
In race two, Matt Neal was excluded from third when his Civic Tourer failed the rideheight test, while MG rival Jason Plato was handed a 10-place grid penalty for the third race for taking off Alain Menu at Clervaux.
Earlier, Giovanardi was fined £500 and received three penalty points for contact with Aron Smith in race one.
He was also demoted to the back of the grid, but the team appealed. The appeal was lost at the end of the day, meaning the Ford driver will start the first Snetterton race from last.
Jordan was also handed a one-second penalty in race one, dropping him from fifth to sixth, after contact with Neal on the opening lap.
Aside from BTCC champions, Martin Depper received a three-second penalty for contact with Sam Tordoff in race three, while Rob Collard will take a five-place grid penalty at Snetterton for hitting Jack Goff at Sunny in the finale.
The revised championship top six is thus:
1. Colin Turkington (WSR BMW) 228
2. Gordon Shedden (Dynamics Honda) 221
3. Andrew Jordan (Eurotech Honda) 200
4. Jason Plato (Triple Eight MG) 179
5. Rob Collard (WSR BMW) 170
6. Mat Jackson (Motorbase Ford) 138