Drivers are marking the last day of ULEZ freedom before Sadiq Khan's unpopular expansion comes in at midnight tonight.

A mass drive of non-compliant vehicles is taking place this morning in Brentford, West London - as the capital braces for a wave of protests by furious motorists.

The £12.50 charge will generally affect petrol vehicles introduced earlier than 2005 that are not compliant with Euro 4 emissions regulations.

Meanwhile, diesel cars and vans will only be exempt if their engine complies with more recent Euro 6 rules, which were introduced in September 2015.

This will snare popular vans registered before the cut-off date including Ford Transit Custom 310s.

The ULEZ charge will snare popular vans registered before the cut-off date including Ford Transit Custom 310s

Diesel cars that will also be liable include the Volkswagen Golf SE Bluemotion Tech TDI (2014 registration)

Drivers of the Seat Leon FR TDI (2014) will also have to pay £12.50 a day to take it into London

Diesel cars that will also be liable include the Volkswagen Golf SE Bluemotion Tech TDI (2014 registration); the Seat Leon FR TDI (2014); and the Vauxhall Corsa 1.3 1.3 CDTi ecoFLEX Excite Hatchback (2014).

Affected petrol cars include the Ford Puma Mk1 (2001) and the Honda Civic 1.6i LS Limited Edition 5dr (1998).

Today, a rush of people heading to Transport for London's online checker to see whether their car is compliant caused technical issues, with the website warning of delays.

Anti-ULEZ campaigners have ramped up the pressure on Mr Khan by leaving a caravan covered with protest messages parked outside his home in Tooting.

The mobile home - which has been dubbed a 'Khan-ovan of hate' - describes the Mayor as the 'dictator of London'.

Other messages include a picture of the Mayor next to quote marks reading: 'Pay me £12.50 and you can pollute for 24 hours' and multiple proclamations to 'sack Khan.'

One local, who spotted the caravan, said the expansion of the scheme has sparked anger among people in the area.

The Vauxhall Corsa 1.3 1.3 CDTi ecoFLEX Excite Hatchback (2014) is another popular diesel model that is liable for ULEZ

Affected petrol cars that fall foul of the new emissions standards include the Ford Puma Mk1 (2001)

Anyone with a Honda Civic 1.6i LS Limited Edition 5dr (1998) will also begin ramping up a hefty bill

Today, a rush of people heading to Transport for London's online checker to see whether their car is compliant caused technical issues, with the website warning of delays

The resident said: 'I saw the van this morning driving up towards the common. I burst out laughing I had to get a picture of it.

'The mayor has lived here for years and it's never bothered anyone. But all of a sudden these cameras have appeared so now people are really angry.

'No one wants these new zones and they're really going to impact people.

'If you can afford the fines or a new car you can crack on, but if you can't you have to spend thousands.'

In photos shared to a Facebook group named Action Against Unfair Ulez, several Ulez protesters expressed their support for the stunt.

One wrote: 'Fantastic, well done.'

Another bragged: 'I drove past it today in my non Ulez van - Great work.'

It is unclear if members from Action Against Unfair Ulez were behind the stunt.

Despite the weight of opposition, Greater London Authority planners insist that nine in 10 cars and eight in 10 vans already meet the Ulez standards - covering all petrol vehicles from 2006 and diesel vehicles from 2016.

Local resistance to the plans has seen some Ulez cameras vandalised, as thousands of new units are installed in outer boroughs of the capital.

Gangs of so-called 'blade runners' have been cutting cables on newly installed cameras, or covering the lenses with stickers that read 'FCUK KHAN'.

Nearly nine out of 10 Ulez cameras have been vandalised in southeast London, according to an analysis of crowd-sourced data.

Mr Khan's Ulez expansion has been heavily criticised by some Londoners

A caravan covered in ULEZ protest slogans has been chained close to Mr Khan's house

It is covered with warnings including 'ULEZ will be your Poll Tax Mr Khan' and claims 'ULEZ is a cash grab'.

The van also features a picture of the mayor accompanied by a speech bubble stating: 'Pay me £12.50 and you can pollute for 24 hours'

The data shows that only 29 cameras out of 185 in Sydenham are working, only four are intact in Bromley and just one is working on the A225.

TfL has said the vandalism will not stop the Ulez changes going ahead this week as planned and that all vandalised cameras will be replaced or repaired.

A spokesperson added that more than 1,900 cameras are in place in outer London.

Meanwhile a top motoring lawyer, known as Mr Loophole, has advised that drivers who enter newly expanded Ulez zones without encountering warning signs will have grounds to challenge their fines.

Nick Freeman, who describes himself as 'Britain's highest profile lawyer' and who has got a string of high profile figures off driving offences has suggested the fines themselves 'could be invalid without warning signs.'

Six out of the seven local authorities immediately bordering London have refused to sign a legal agreement with Transport for London (TfL) to allow Ulez signs within their borders.

The act of protest has been mounted by Surrey County Council, Kent County Council, Essex County Council, Hertfordshire Council, Buckinghamshire Council and Thurrock Council, which are Tory-led and have been vocal about the financial impact Ulez will have on its residents.

The only council that signed an agreement was Slough Borough Council, which shares the smallest border with London and only has two signs installed.

Speaking to the Telegraph, Mr Freeman explained that this has the potential to create very real issues for London Mayor Sadiq Khan.

How the Ultra Low Emission Zone has expanded across London throughout the years

Nearly nine out of 10 Ulez cameras have been vandalised in southeast London , according to an analysis of crowd-sourced data

He explained: 'Any road traffic regulations that are introduced, there must be clear, unambiguous signage.

'And in the absence of clear, unambiguous signage, no penalty can be enforced. The prosecutors would, I'm quite confident, win on appeal.

'This happens in speeding cases, you get it in bus lane cases, there are a whole host of cases where the signage isn't clear.

'And then when somebody wants to challenge it, they invariably win because the signage doesn't doesn't fit the bill.'

This quandary was also identified by Edmund King, the president of the Automobile Association, who suggested that TfL could be swamped with driver complaints.

He told the newspaper: 'If TfL does not send out warnings they will be deluged with complaints from drivers. If they turn down appeals to have fines cancelled, huge numbers will take their complaints to the traffic penalties tribunal.'

A TfL spokesman said: 'All the signs needed for the enforcement of the scheme will be in place and the boundaries clearly signposted for residents.

'The signage and level of information in the public domain means we expect drivers to be aware of the standards and the boundary. This means all non-compliant drivers are liable for the charge and if they fail to pay it within the appropriate amount of time, they will face a penalty charge.

'National Highways, which manages the busiest roads into the capital, have worked with us to ensure drivers have advance warning of the expanded Ulez, and we have run a major communications campaign to make sure as many people are aware of the scheme as possible.'

Nick Freeman, a top motoring lawyer, known as Mr Loophole, has suggested that some drivers may be able to appeal fines

From next week, the controversial scheme will will cover all London boroughs and will force drivers of non-compliant vehicles to shell out £12.50 a day

Local resistance to the scheme has been fierce in some areas of London with signs installed beneath cameras to warn drivers