Hundreds of motorists are said to have been wrongly fined on a stretch of road in south-east London after a "poorly signposted" new speed limit was introduced, according to a lawyer who is fighting their corner.
Transport for London (TfL) has introduced a 40mph limit along part of the eastbound A20 near Sidcup in October, due to concerns over water flooding the road.
But thousands of speeding tickets are believed to have been issued to motorists who have driven along the stretch, unaware of the change.
Chartered legal executive Dominic Smith, director at traffic solicitors firm Patterson Law, is calling for the fines to be overturned.
He says the 40mph signs were "small", while a "rogue 50mph sign" placed on the stretch also misled drivers.
The Met police is investigating who erected the 50mph sign, which it is treating as a potential crime. But it claims it would not have led to extra speeding tickets in the area, which is covered by an average speed camera.
Meanwhile TfL, which is responsible for signage, says the 40mph signs are compliant with regulations.
Mr Smith told the Standard he has been inundated with messages from drivers who feel they have been wrongly fined.
He understands around 62,000 fines have been issued along the stretch of road since mid-December, though police have not been able to confirm the figure.
"It's not just unprecedented, it's just in a different ball park from anything I've seen before," Mr Smith said. "It's huge. I've never seen anything like this."
Mr Smith set up a Facebook group for people who have been fined along the road, which has now attracted around 1,400 members.
"The big question that the police have got to answer was about the signage and whether it was adequate," he said.
Mr Smith says he has contacted the police, saying those who have been fined should not be prosecuted because the signage "isn't good enough".
He told the Standard some drivers have unwittingly sped through the stretch "eight, nine, or 10 times" before realising the speed limit had been changed to 40mph.
One driver, David Owen, told the BBC he received a notice saying three points would be added to his licence after he unknowingly sped on the stretch of road.
"I know I've been on there two further occasions since, before I was aware of the speed change, so I'm waiting for the next fine and the next points to come through," he said. "It's a waiting game, and you just feel powerless to do anything."
Local resident Serena Brooks, who has also received a fine, told the BBC: "I am an aware driver. I think it's just because I've been driving that stretch of road almost daily for goodness knows how long, and I think it just needs to make it really clear.
"I feel like it's been a bit of a trap really. Considering there have been so many other drivers who have been caught out, I think something needs to change."
The Met and TfL are both investigating who erected the 50mph sign, which has now been removed.
A Met spokesperson said: "On January 24 we were informed that a 50mph sign had been placed on a section of the eastbound A20 in Sidcup where the speed limit had recently been reduced to 40mph. The sign has been removed.
"We have confirmed that it was not placed there by the Met or Transport for London and we are investigating this as an attempt to pervert the course of justice."
The spokesperson added: "Our prosecutions team, which deals with speeding offences, has taken legal advice and the location of the 50mph sign would not have impacted the enforcement of the 40mph average speed limit."
A TfL spokesperson said: “Safety is our number one priority and we have temporarily introduced a 40mph speed limit on the A20 Sidcup Road due to ongoing surface water flooding which has caused a number of safety concerns and serious risk to road users. The reduced speed limit has been introduced in response to that risk.
“Major work is required to put in place permanent measures to tackle flooding here and we are working to do this as soon as possible. We plan to begin construction work on these measures in May.”