Previously winless Essex were asked to bat at a sun-baked Chelmsford, and promptly smashed an inexperienced Surrey attack to all parts for their record One-Day score.
Matt Critchley made 58 at the top of the order and Luc Benkenstein hit 83, but it was the partnership between Campher and Simon Harmer that provided the fireworks.
They added 175 in under 16 overs as Campher, in the first of just three games for Essex in this competition, walloped 12 fours and six sixes in his highest-ever List A score off only 68 balls, with Harmer equalling his best in this format with 68.
Surrey were never in a position to threaten Essex’s mammoth total with Cameron Steel’s 49 the only modicum of resistance.
Bennett took 5-36 in only his fourth game at this level as Essex put a seal on their remarkable 244-run victory.
The result was record defeat for Surrey in the competition, and they sit second bottom of Group A with one win from four games.
Worcestershire are now top of the group with three wins and a tie, but they were under pressure when Derbyshire’s Caleb Jewell and Matthew Montgomery were together.
In the grounds of Repton School, their 150-run partnership took them to 196-1 in the 32nd over.
But Australian Jewell went for 113 and Montgomery eight short of his century as Derbyshire slipped to 315 all out, crucially with 17 balls not used up as Ben Allison and Khurram Shahzad claimed three wickets apiece.
The Rapids were soon 11-2, but Brett D’Oliveira and Jake Libby (69) turned things around with a stand of 183.
D’Oliveira was eventually out for a personal-best score of 138 off 118 balls to leave Worcestershire 272-5, but 19-year-old Daniel Lategan on debut steered his side home on 42 not out by four wickets with 11 balls to spare.
Hampshire made it three wins out of four with a strong display to see off Leicestershire Foxes at the Rose Bowl.
The visitors batted first, but were kept in check by some fine bowling from South Africa seamer Kyle Abbott up top as he eventually finished with 3-36.
Sol Budinger (65), Shan Masood (57) and Ben Cox (55) all passed 50, but the Foxes were eventually bowled out for 252 in the penultimate over.
In reply, a magnificent opening stand of 202 between Ali Orr and captain Nick Gubbins set up the victory.
Gubbins went for 81, and although Orr perished for a terrific 131 in sight of the winning line, Hampshire completed their seven-wicket success with 6.3 overs to spare.