The rise of 20mph zones under Labour has sparked a huge surge in the number of drivers caught speeding in them, sparking renewed accusations of a 'war on motorists'.
Figures show drivers ensnared by speed cameras in the controversial zones soared from 21,125 in 2023 to 127,915 last year - a staggering 500 per cent jump.
Data from 22 police forces found nearly 250,000 in total were handed fines, had to go on a speed awareness course or were given licence penalty points over the three-year period.
In some areas, the number of motorists clocked speeding on 20mph roads surged by an astronomical 50,000 per cent after new zones where the top speed was lowered from 30mph or 40mph were created.
Not all 43 forces in England and Wales responded with data - including Scotland Yard, the country's biggest force - meaning the figures will likely be much higher.
Critics pointed out the biggest increases in drivers being ensnared were in Labour-run areas and accused the party of treating drivers like 'cash cows', as fines raise tens of millions of pounds annually and are paid to the Treasury.
While there is evidence 20mph limits reduce drivers' average speed, motorists complain they are often introduced on roads where they are not needed and that the growing number of them has created confusion, catching out otherwise law-abiding drivers.
The Tories' shadow transport secretary, Richard Holden, said: 'There's no clearer sign of Labour's war on motorists than their blanket 20mph cash cow fine machine being imposed by Labour in Wales and Labour and Lib Dem councils across England.
The number of 20mph zones across Britain has steadily increased in recent years, with more than a sixth of roads now having a 20mph speed limit
Around 39,000 miles of the nation's 246,500-mile road network are now 20mph zones, according to the transport consultancy Insight Warehouse
'Labour's blanket 20mph approach has gone far past any evidential or common sense threshold, hitting roads that never needed them, creating confusion on streets where the old speed made sense, and otherwise law-abiding drivers being criminalised for it.
'Conservatives are on the side of drivers. That's why we will end the blanket use of 20mph limits and see their use limited to where they benefit people, not used as another way to attack motorists.'
Howard Cox, founder of the FairFuelUK campaign, said: '20mph speeding fines are simply an easy-to-capture revenue stream that flows centrally rather than directly funding local budgets.
'The huge increase in these opportunistic cash grabs, mainly in Labour-run areas, stinks and highlights the government's anti-driver war on motorists to fund its fiscal incompetence.'
Steve Gooding, director of the RAC Foundation, said: 'A 20 mph limit might make perfect sense outside schools or in busy shopping streets, but on other roads the lower limit might feel much less intuitively appropriate, particularly on wider streets.'
The highest increase was recorded by North Wales Police, which said just 109 drivers were caught speeding in 20mph zones in 2023.
But this surged to 54,259 last year - a staggering 50,000 per cent jump.
Over the three-year period, the force caught 109,569 drivers in total.
It was after the then Labour government in Wales blanketed its roads with 20mph zones in 2023 after lowering the default limit on most residential and built-up roads from 30mph.
Merseyside Police, which covers an area controlled by Labour councils, saw the second largest increase in percentage terms.
It caught 89 drivers speeding in 20mph zones in 2023, which soared to 13,148 last year - a surge of 15,000 per cent. Over the three year period it ensnared 20,566 drivers.
The Tories' shadow transport secretary, Richard Holden, said the latest 20mph speeding figures were proof of a 'war on motorists'
Howard Cox, founder of the FairFuelUK campaign, said 20mph speeding fines were 'simply an easy-to-capture revenue stream'
Meanwhile, West Yorkshire Police, another area run by Labour local authorities, caught 624 drivers speeding in 20mph zones in 2023, jumping to 24,882 last year (3,900 per cent).
It caught 40,431 drivers breaking 20mph speed limits over the three year period.
Local authorities largely decide whether to create 20mph, with police forces enforcing them and cash from fines going directly to the Treasury.
The number of 20mph zones across Britain has steadily increased in recent years, with more than a sixth of roads now having a 20mph speed limit.
This equates to around 39,000 miles of the nation's 246,500-mile road network, according to the transport consultancy Insight Warehouse.
Along with the overhaul in Wales, more than half of London's roads now have a 20mph limit, according to Transport for London, which is chaired by Labour mayor Sir Sadiq Khan.
In Leeds, where Labour was in control until this year's local elections, dozens of roads have become 20mph as part of the city's Vision Zero policy.
This aims to eradicate all traffic fatalities and serious injuries on the city's roads by 2040.
Other cities in Yorkshire that have signed up to the policy include Sheffield, Bradford, Wakefield, Huddersfield, Halifax, York, Kingston upon Hull and Doncaster.
Dozens of other town halls across the UK have introduced new 20mph zones or are planning to.
A Department for Transport spokesman said: 'Local authorities are responsible for setting speed limits in their areas, and our guidance is clear that 20mph limits should only be used where they are appropriate and supported by evidence.
'Speed cameras are for safety, not raising cash.'