Asda has hired Trolleywise to collect errant trolleys and return them to its 150 worst-affected stores.

Trolleys are lost through abandonment, theft for scrap metal and councils removing them under the Environmental Protection Act (EPA). Asda estimated it would recover 20,000 trolleys a year, although Trolleywise said the figure could be much higher.

With new trolleys costing £100 and other Trolleywise contracts averaging £3.50 per returned trolley, this would save it £1.9m.

Asda would not comment on the potential cost savings, but Julian Walker-Palin, head of corporate policy for sustainability and ethics at Asda, said: "By not buying the trolleys in the first place they won't need to be manufactured. This will save more than one and a half million kilos of carbon every year."

Trolley losses had been exacerbated by over-vigilant councils, said Trolleywise contracts manager Stewart Turner. "The EPA allows councils to seize trolleys off the street and fine the retailer. Councils are supposed to give the retailer time to collect the trolley but a lot whip them off the street and fine them."

Trolleywise now audits Asda's losses. "We attend the worst store twice a day and pick up 150 trolleys daily from surrounding estates," said Turner.