It's 60 years since the Colin Chapman inspired iconic Lotus Seven hit the streets and it's fitting that its lineage continues with the Caterham 7 Championships starting the models Diamond celebrations off at Snetterton this weekend.

The series for the fastest of the current breed of '7' is the 420R Championship which can lap the Snetterton 300 at an average speed in excess of 85mph and, with title holder Aaron Head moving on, the field is wide open.

Suffolk racer William Smith clinched the Supersports title last year and moves up a rung to the 420R's for this season and has shown the speed to put a championship challenge together but Lee Wiggins and Jack Sales, Head's leading opposition last year, will take some defeating.

Jack Brown and Henry Heaton were in Smith's wheel tracks last year in the Supersports title race with a tie break required to split the pair, with Heaton back for another tilt at the title.

Peterborough-born Anthony Barnes maintained his grip on the former Tracksport championship, now renamed the 270R series, until the end of the season but was unable to defeat Matthew Lambert in Norfolk last year while Roadsports winner Russ Olivant moves into the series this year.

When the Roadsports visited Snetterton last year Olivant couldn't quite take victory as Guy Hawkins stole the limelight and, with Tom John moving up from the Caterham Academy series, it will ensure another tight battle for the title.

The 310R Championship is new for the 2017 season with 'old hand' Gordon Sawyer one to watch as the series kicks off at the Norfolk venue.

The Quaife Modified Saloons makes its only journey away from Brand Hatch this weekend with title holder Rod Birley hoping to secure his 600th career victory with his Ford Escort WRC.

The Peterborough built Radicals are the mainstay of the Open Sportscar Series but Richard Wise in his Chiron will be hoping to break up the near monopoly of late.

Completing the 17-race programme are events for the Intermarque series, featuring Ian Hales from Foulden, with racing starting at 1.30pm on Saturday and continuing from 9.30am on Sunday.