Defenders: Busting the Bad Guys

With knife crime on the increase, officers go undercover in Birmingham to find out which shops are illegally selling knives to children. They meet the family whose lives were ripped apart by a random knife attack carried out by two boys aged just 15 and 17. They track down the boss of a car park scam. He is making a fortune offering premium parking facilities and then dumping the cars in a muddy field. And they crack down on the sale of dangerous skin-whitening creams that damage the skin and put lives at risk.

In Oldham, officers are cracking down on rogue landlords housing families in squalid conditions. They also jail a con man who has been posing as a collector for a children's cancer charity, but is keeping all the money for himself. In east London, officers have set up a bi-weekly online TV programme to name and shame local fly tippers. They post footage of perpetrators online, and when the culprits are identified, they are hit with a £400 fine. As a result, fly tipping has fallen by a third. Following a tip off, a large scale fly tipping gang are busted for illegally dumping 250 tonnes of waste on private land.

As a spate of acid attacks across the UK make the headlines, officers go undercover to stop retailers selling acid to teenagers. In a 3am stop-and-search operation, police take to the streets around Birmingham to target vehicles carrying fake or potentially dangerous imported goods to car boot sales in the region. And officers catch up with mother-and-daughter letting agents in Cornwall who have pocketed a quarter of a million pounds of other people's money.

Enforcement agents shut down a filthy takeaway in Greater Manchester that is infested with mice. They also investigate a salmonella outbreak that struck down over 50 guests at a wedding after a hog roast was served dangerously undercooked. Officers are also on the trail of fraudsters targeting our bank accounts. A 91-year-old pensioner and retired fireman lost nearly £15,000 of his savings when he was cold-called by people he thought were from his bank but were actually scammers.

Officers crack down on illegal and dangerous vehicles putting our lives at risk. Marathon runner Allan Wood almost lost his life when he was mowed down by a vehicle that hadn't had an MOT for over three years and had no working brakes. They also discover an illegal puppy farm in Cannock that is putting profit ahead of care. Thirty dogs and two racoons have been kept in filthy conditions, some of them locked in old cars, with no water, food or proper ventilation. And a rogue kitchen trader that has swindled customers out of thousands of pounds is shut down.

Officers swoop on an illegal sweatshop in Birmingham suspected of being a major supplier of counterfeit clothing. Inside they discover thousands of garments and banks of manufacturing machinery - it's one of their biggest finds ever. They are also on the trail of a cowboy builder who all but destroyed a young family's dream home, ripping off the back of their house and digging up the garden, leaving the property unliveable and the family close to £17,000 out of pocket. In Newcastle, enforcement agents catch up with a criminal fly-tipping gang who are putting profit before public health. Fly tipping costs the city nearly half a million pounds per year to clean up. And a consignment of cheap earrings which could contain dangerously high levels of base metals such as nickel are seized.

At Victoria coach station in London, officers are on the lookout for coach drivers who are driving when they are too tired. We hear from the mum of 23-year-old Nathan Reeves, who was killed when the vehicle he was travelling in was hit by a coach whose driver is thought to have fallen asleep at the wheel. They also track down two fraudsters running a sim swap scam and stealing almost half a million pounds from victim's bank accounts, and we find out about the new thermal imaging technology being used in Oxford to spot garden sheds that are being rented out illegally as homes.

At Felixstowe docks in Suffolk, enforcement agents are on the hunt for counterfeit and dangerous goods, stopping them entering the country. They also chase down a gang that has been bullying elderly people into having unnecessary building work done on their home, including one pensioner who paid out over £300,00 - almost his entire life savings - for work that should have cost around £30,000. And they hunt down a gang who callously dumped tons of illegal waste next to a motorway in Hampshire.

Officers bust a tenant making over £100,000 unlawfully sub-letting his council flat in London. They take down a criminal gang running a multi-million-pound diesel fraud. The gang has been contaminating diesel with cheaper products, which is saving them millions of pounds in tax and costing unsuspecting motorists thousands of pounds in engine repairs. And they help rescue over 150 dogs being kept in squalid conditions at an animal centre in Lincolnshire.

In Birmingham, officers crack down on a callous travel agent that is ripping off British holidaymakers, taking their money but never booking their flights. They are also on the trail of a crooked builder who befriended a pensioner in order to take his money, and they take to the streets to spot check luxury limos being driven in London. We hear the story of one limo that was driving a school party of 11-year-olds when it burst into flames.