One of the largest crackdowns on the reseale of stolen goods has been carried out by the Metropolitan Police.

Officers visited about 400 shops, market stalls and car boot sales, leading to 42 arrests and 11 closure orders for shops.

Deputy Commissioner Matt Jukes said about 100 prolific shoplifters were responsible for 4,000 offences across London and the force was "going up the food chain" to target the businesses and criminals profiting from theft.

BBC London joined officers during a raid on a phone shop in Electric Avenue, Brixton, where three men were arrested on suspicion of handling stolen goods.

Police said the raid followed months of investigation after reports that stolen phones were being brought to the Brixton shop and sold on.

Insp Martis Jones said it was "not proportionate" to go through every device at the street side so they decided to seize them all to check at the police station.

The Brixton raid was one of dozens carried out across London during the operation.

In Hounslow, officers seized five pallets of suspected stolen tools, as well as counterfeit Dyson products.

Suspected stolen food products were found in shops in Lewisham, Clapham and Southall, while searches also uncovered cash, drugs, weapons and suspected stolen identity documents.

The Met said it had issued warning notices to car boot sale organisers for the first time, making clear they could face criminal liability if they knowingly facilitate or ignore the sale of stolen, counterfeit or illicit goods.

Jukes said police were increasingly targeting the networks that profit from theft, as well as the people carrying it out.

"We know that, on high streets like this one, businesses are suffering because of the thefts they experience, and we're even seeing businesses that are themselves receiving stolen goods selling them on.

"So it's affecting shopkeepers, it's affecting quality of life and, look, who wants to go into a shop and see someone clearing the shelves when you're under pressure yourself to spend your own money and then you see that happen?

"So it matters. It matters to businesses, it matters to people's sense of safety in London," he said.

The Met also said that they were working with retailers to protect the products most commonly targeted by thieves by marking them with SelectaDNA, a forensic marking solution that leaves a unique traceable code visible under UV light.

Jukes said: "It's like chemical DNA that we can identify. We can track back to the place that property was stolen, which means we can actually start to shut down those businesses that are receiving stolen goods to sell them on."

Police said the operation was not aimed at small businesses, but at those selling stolen goods and undercutting legitimate retailers.

"People do know about that vape shop that no one ever goes into, that phone shop that doesn't look quite right, or that convenience store that's got too-good-to-be-true prices," he said.