A special report by Hamish Auskerry and Jon Wilson
It's 5pm in a Newport police station and officers from across the Gwent patch have gathered in a briefing room.
Tonight they will all take part in a covert exercise as part of Operation Harley, which tackles the use of electric off-road bikes being on the city's roads and pavements.
"These vehicles are being used by Organised Crime Groups (OCGs) to facilitate the supply of drugs around the city", PS Mark Sexton tells his colleagues during the pre-operation briefing.
"They're illegal to use and the people who are riding them are generally using them for illicit means and criminality".
PS Sexton says they are often driven fast along footpaths and public highways in a way that endangers the public.
This is a hard crime to police. Police are not usually allowed to pursue active riders by car because of the danger it puts the suspect, the public and the officers involved.
Officers say the issue of illegal e-bikes is one of the most commonly raised in police meetings in local communities.
"It's got increasingly worse over the last few years", Inspector Roland Giles tells me.
"We receive hundreds of calls in Newport alone every year reporting and social use on e-bikes get complaints from local people and councillors.
My cameraman Jon Wilson and I headed out with the team in an unmarked van with plain clothes police officers.
Letters have been places on the dashboard alongside some fluorescent tabards, because police must use stealth and some trickery to catch suspects when they least expect it.
A call comes in over police radio of an illegal-type bike nearby. Officers attend and arrest a man at the scene. When we arrive, the suspect has been injured. Police say his e-bike fell on him and now he has a suspected broken leg.
Gwent Police have since voluntarily referred themselves to the Independent Office of Police Conduct (IOPC), which is the standard practice when anyone is injured in connection with police activity. The suspect is still receiving treatment for his injury.
"They are a menace to the road at the moment if you ask me", Joe Clark tells me. Joe is a Community Support Officer (CSO) with Gwent Police, and he joined colleagues as part of this operation.
"They need to have better regulations and be taken off the roads in my opinion", he said next to the bike that had just been confiscated.
He says the telltale signs that the bike was being used illegally are that it had no licence plate, the back tyre was bald, and it was an off-road type bike, only allowed to be ridden on private land.
Operation Harley was started in 2018 to tackle the issue of off-road bikes being used to cause criminal damage in the more rural parts of the Gwent patch.
Inspector Giles says the situation has been worsened by electric bikes, which can potentially be driven faster and more dangerously than the petrol equivalent.
Electric motorbikes, which are much more powerful than the standard commuting electric-assist pedal bike, are only allowed to be used on private land. Owners who want to use them on roads would have to ensure the bike is taxed, and insured and the rider has a driving licence.
"It's really important for us to find out where these bikes have been ridden more often. So we attend those hotspot areas where we know the bikes have been used. And we try and detain them without having to go through a chase or pursuit scenario".
Inspector Giles encouraged members of the police to get in touch with police to report anti-social behaviour in connection with the use of e-bikes and said officers take those reports seriously.
There have been occasions, Gwent Police say, where riders of e-bikes have targeted police vehicles: throwing stones and bricks as they pass by. On some of those occasions, it has been logged as a "near miss" for serious injury to an officer.
Up to the 16 October, Gwent Police say they have seized 139 bikes in total. 39 of them were e-bikes, and the rest were the petrol off-road equivalent.
We witnessed one more being taken off the streets during this covert operation. Gwent Police will now try again to catch more when they next do the same exercise, in 4 to 6 weeks.
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