Trading standards officers are warning the public they could turn Bonfire Night into a tragedy or damp squib if they do not buy fireworks from established businesses.
They are advising consumers to steer clear of fireworks offered for sale in “unofficial” venues like pub car parks, markets, car boot sales or street corners.
Fireworks purchased from these outlets may be dangerous. They may also be of poor quality and simply not work.
Anyone selling fireworks needs to be registered with their local trading standards department.
This is to ensure that the fireworks meet safety standards and are being stored correctly. Trading standards officers can also monitor registered retailers to ensure they are not committing an offence by selling to the under-18s.
Wandsworth's chief trading standards Les Eames said: "Across the country there have been instances when consignments of fireworks have been discovered that were downright dangerous. They were not even close to meeting EU and UK safety standards.
"There have also been examples of fireworks with no safety guidance and others that were literally falling apart. Fireworks like these could cause serious injury to anyone handling them or watching, so buying from itinerant or unusual sources can be a risky thing to do.
"It is an offence to sell fireworks to people under the age of 18 and young people are banned from possessing them in a public place.
"But unfortunately it is these kind of unofficial venues that are much more likely to flout the law on under-age sales. It is these kind of unscrupulous businesses that are making money by fuelling the anti-social behaviour communities experience when fireworks are let off late at night.
"And it is these 'here today, gone tomorrow' traders that are profiting from the sale of potentially lethal fireworks to young people.
"That is why we are urging people to steer clear of these traders and appealing for information that can help us track them down."
Anyone with information about illegal firework sales in Wandsworth can call (020) 8871 7720 or the national Consumer Direct helpline 08454 04 05 06.