Rusting away in a river or slung in a ditch, the discarded supermarket trolley is one of the less endearing images of 21st Century supermarket shopping.

Now stores in West Norfolk face being fined £100 for each trolley which is picked up bearing their names, in a council crackdown on fly-tipping.

Officials have hired a specialist company to recover those which have been left behind by shoppers.

Exeter-based TCS - Trolley Collection Services - has signed up for a three-month trial, covering King's Lynn, Downham Market, Hunstanton and surrounding areas. The firm says it will collect any trolley which is reported to it within 24 hours.

Brian Long, West Norfolk's cabinet member for environment, said TCS will charge stores £100 for each trolley and split the money 50/50 with the council.

'In the two weeks it's been going they've collected 97 trolleys,' he said. 'There's a lot of trolleys dumped around the borough making it look untidy.

'The problem with it is they can attract other fly-tipping. Once someone leaves a trolley somewhere, someone else comes along and dumps a bag of rubbish in it.'

Councils have powers to charge stores a 'fine' for collecting trolleys under parts of the 2005 Clean Neighbourhoods and Environment Act.

'If the supermarket doesn't collect them and they go to be recycled, they still have to pay the fine,' said Mr Long.

Blackspots in Lynn have included the Long Ponds, Nar Loop, and the Bawsey Drain - a stream which flows behind the North Lynn retail park. Yesterday, the wheels of one trolley could just be seen above the water, which had been swollen by recent rain.

Some estimates put the number of trolleys dumped each year as high as 1.5m. As well as a hazard to wildlife, those dumped in waterways can also obstruct flows and increase flood risk if they become covered in weed and other debris.

Another recovery programme, Trolleywise, has been backed by rivers watchdog the Canal & River Trust. It enables smart-phone users to download an app on which they can photograph and report abandoned trolleys.

A spokesman for the British Retail Consortium said: 'Retailers have a good record on working with local authorities to prevent theft and recover stolen trolleys. They often have deposit schemes or grids at car park exits to make it less likely they will be stolen, and usually if anyone calls a store's customer service line about an abandoned trolley the retailer will go and collect it.

'It's in retailers' interests to do what they can to deter trolley theft, as abandoned trolleys can damage the environment and replacing them is expensive.

'Close partnership with local authorities and working with recovery programmes such as Trolleywise is proving to be a more successful approach than trying to pin the blame or pass on the bill.'

A spokesman for Morrisons said: 'We recover our own trolleys and try to recover as many as possible and get them usable again.'

She added the store was aware of the legislation enabling councils to charge for recovery and would comply with it.

Sainsbury's said: 'We look out for trolleys that are left outside our premises and ask customers to let us know if they spot any abandoned ones. We will always send someone to collect them and where possible we refurbish old trolleys and return them to service.'