While fleet managers were at Company Car in Action, Kwik-Fit Fleet scoured the car park, finding at least 128 faulty tyres on the 1,030 cars it checked.
Kwik-Fit Fleet director Simon English said: 'It is alarming that so many fleet professionals should be driving vehicles fitted with unsafe tyres. Fleet executives should be leading by example and ensuring that the vehicles they drive are in first class condition. It is not only their safety but that of other road users they are jeopardising.'
Failing cars were left with a check sheet and tread depth indicator identifying the problem.
Earlier in the year, checks on fleet cars by Kwik-Fit Mobile revealed 10% of tread depths were below or close to the 1.6mm legal limit. The firm estimated as many as 300,000 company cars could be running on defective tyres.