The one-minute clip, which has since been uploaded to YouTube, shows the barefoot driver signalling to vehicles in the next lane, bringing one van to a stop.
As the van driver switches on his hazard lights, cars in the two inside lanes also stop, bringing the carriageways to a standstill and forming an impromptu barrier across the motorway.
While the traffic had already been slowed to 60mph by the automatic flow system, the driver still put him, and other motorists, in danger with his bold traffic manoeuvre.
The van then escorted the four-wheel drive and the trailer to the hard shoulder. The man is seen giving the waiting motorists a thumbs up as the traffic returns to normal.
PUNCTURE ON THE MOTORWAY: WHAT TO DO IF YOU'RE STRANDED
Superintendent Tony Godwin, Head of Specialist Operations at Avon and Somerset Police reminded drivers that it was an offence for vehicles towing trailers to use lane three of the motorway.
He said: 'If you do find yourself breaking down on the motorway, you should move to the hard shoulder if it's safe to do so, but if you're stuck in lane three then we'd advise you to stop, put your hazard lights on and if the central reservation is big enough, move there and call 999 immediately.'
The AA advises drivers not to change a wheel on the hard shoulder or at the side of the road, and to turn off or pull away from traffic and call for help.
Mr Young, from Bristol, added: 'The guy was so cool as he did this. He was clearly in barefoot and the woman who was driving looked to just be wearing a bikini.
'The van driver is a bit of a hero, as he shielded them the whole way across. I couldn't believe what I was seeing.'
The barefoot man repaired the puncture on the hard shoulder before safely continuing with his journey.
Superintendent Tony Godwin, Head of Specialist Operations at Avon and Somerset police, said they were trying to track down the barefoot man who brought the motorway to a standstill.
He said: 'It's clear from the footage the driver and passenger were trying to get themselves to a place of safety but their actions could have had tragic consequences.
'A motorway is an extremely dangerous place for pedestrians and you should never attempt to cross live fast-moving lanes of the motorway.
'We'll be looking into this incident and making efforts to trace the driver to carry out further enquiries, as it's an offence for vehicles towing trailers to use lane three of the motorway.
'If you do find yourself breaking down on the motorway, you should move to the hard shoulder if it's safe to do so, but if you're stuck in lane three then we'd advise you to stop, put your hazard lights on and if the central reservation is big enough, move there and call 999 immediately.
'Prevention is always better than cure, so motorists should thoroughly check the condition of their vehicles and trailers before setting out.
'Trailers which do not get used as much should be checked for roadworthiness, including checking tyre condition and pressures.
'Tow hitches should be clean and well-greased with the locking mechanism thoroughly checked.'
- Daily Mail
