A man is facing jail after being convicted of mowing down and punching a teenage cyclist after becoming incensed that the boy was able to weave through traffic to to get to the front of a queue.

Michael Hanley, 69, from Greater Manchester, used his 4x4 Jeep Cherokee to knock the 17-year old victim off his mountain bike after the teenager pulled in front of him as he waited at a set of traffic lights, Manchester magistrates court heard.

It was a perfectly legal manoeuvre for the cyclist, who had overtaken a queue of stationary vehicles to get to the front of the temporary lights in the Summerseat area of Bury on 15 October last year.

But it enraged Hanley, who reacted by bumper hugging the back tyre of the bicycle after the lights turned green and repeatedly beeping his horn and flashing his lights. The teenager was eventually sent tumbling to the floor when he tried to veer off down a dirt track, only for the car to clip his shin as it tried to get past.

As the boy lay on the floor, Hanley got out of his vehicle on the dirt track and said: ‘‘Little shit – you’ve done this,’’ adding ‘‘Did you see what he was doing? He was weaving all over the road” to a shocked motorist who pulled over. He then grabbed the teenager’s shirt and punched him in the face before smashing his own wing mirror in a temper tantrum and driving off.

The teenager – whose six-month-old £2,500 bike was written off in the incident – was given a lift home by the other motorist and was treated for bruising to his left shin and left cheek plus a swollen right kneecap.

At Manchester magistrates court, Hanley, who is director of Smithfield estates management company, was found guilty of dangerous driving and common assault following a trial.

He lied to police and tried to claim the teenager had hit a pothole and come off his bike, the court heard. “I couldn’t use my vehicle as a weapon because the braking mechanism would stop it,” he had claimed, adding: “I have no problem with cyclists – there should be more cyclists on the road. I used to be a cyclist. But if we all stayed behind cyclists and never overtook, the whole world would come to a standstill.’’

But an eyewitness told a different story. Georgina Cullen, who was driving behind Hanley, told the court how she saw him “driving extremely close and beeping aggressively” behind the boy. “The cyclist was clearly trying to get away from the situation, but the vehicle accelerated after him and the impression I got was the car was chasing after the cyclist, drove at him and hit him,” she said. “I couldn’t believe what I was witnessing. I was extremely concerned for the wellbeing of the cyclist.”

She said Hanley falsely accused the boy of “weaving all over the road” before grabbing his arm, punching him in the face and then ripping off his own wing mirror.

She told the court: ‘‘I think I actually said: ‘That’s someone’s son. He wasn’t weaving, he was trying to tell you that there was no room.’ … I was just in disbelief that someone could use a vehicle in such a manner and purposefully hit another human being.’’

Giving evidence via video link, the boy said his confidence had been shaken by the attack: “The incident has affected me quite badly and I wasn’t fully myself for weeks following it. I lost my confidence and from now on I’ll feel more cautious on the roads if I get another bike.’’

Hanley will be sentenced later this month. He was granted bail.