An officer begged a teenage motorist to stop as he was dragged along by the vehicle he was driving.
PCSO Kieron Poole was terrified he would fall under the wheels of Muhammad Nadeem’s car.
The teenager ignored his pleas and drove on, dragging the officer almost 30ft before he got free.
The incident happened on January 25 last year in a car park in Smethwick, West Midlands.
PCSO Poole had smelt cannabis and asked Nadeem to switch off the engine, West Midlands Police said.
In shocking bodycam footage of the incident the terrified officer can be heard begging Nadeem to stop.
Instead the then 18-year-old sped away.
Eventually, PSCO Poole broke free and took the keys with him.
Nadeem fled on foot and was followed by the officer towards Smethwick High Street.
Kieron followed Nadeem for around five minutes and guided colleagues in to make the arrest.
In the car was a hammer and an axe, and Nadeem had a small amount of cannabis on him, the force said.
Nadeem, now 19, of Florence Road, Smethwick, said he was “shocked” when shown the footage and admitted it “doesn’t look good”.
The teen admitted assault occasioning actual bodily harm, dangerous driving and possession of an offensive weapon.
He will be sentenced at a later date.
PSCO said the driver “seemed quite friendly at first”, but all that changed once he’d confronted him about the cannabis.
He said: “It all happened so quickly. Before I knew anything my arm was attached to the car and I was being propelled, hanging on the side, through a couple of branches, a good 20-30ft before I knew what was happening.
“I shouted ‘Stop! Stop!’, but he wasn’t paying any attention.
“I knew I had to get the key out of the ignition. If I didn’t, I could have gone under his tyres and I might not be here today.
“I decided I’m not going to let him sit back and get away with that.
“I instinctively chased him. He was cornered and I was hoping he’d give up.
“Instead, he decided to rush towards me with a bottle and quite forcefully hit me at the side of the head with a plastic bottle.
“My adrenaline was going so I felt like I could carry on trying to pursue him.
“He started walking quite casually up the street, but I didn’t want to get too close at that point thinking he could have a weapon, he’s already hit me over the head, he’s clearly going to resist, so my best course of action was to wait for the local neighbourhood units.”
Kieron was left with a bruised arm but no serious injuries.
He said: “It’s made me more cautious – I didn’t want to have a break from doing my job, I felt like that would have been more of a barrier to me.
“But I wanted things to be as normal as possible really because I didn’t want it to affect the way I worked within the community.
“I’d like to thank the quick response of the neighbourhood officers who arrived within minutes to help me.”