More than 200 vehicles that fell foul of London’s ultra-low emission zone (Ulez) have been sent to Ukraine to aid the country’s war effort, despite initial legal concerns over the plan.

Transport for London (TfL) said on Friday that 330 vehicles had been given the green light to be sent to Ukraine under the Ulez vehicle scrappage scheme. More than 200 are already in the eastern European country.

The vehicles will be used exclusively to support humanitarian and medical aid efforts in the country, as it tackles the full-scale invasion by Russia, which began in early 2022.

The Ulez scrappage scheme, launched in January 2023, gives drivers grants to contribute towards buying a Ulez-compliant vehicle if they scrap a vehicle that does not comply with the air quality zone’s emissions standards.

Drivers with the most polluting vehicles must pay a £12.50 daily charge under Ulez, which was expanded to outer London last year despite a backlash.

In March, drivers using the scheme were given the option to be paid to send their vehicle to Ukraine instead of having them scrapped after campaigners pushed the government and the London mayor, Sadiq Khan, to support the idea.

The number of vehicles now in Ukraine was revealed by TfL as it prepares to close the Ulez scrappage scheme on 7 September. Drivers, businesses and charities have received more than £186m after 53,944 applications were approved to dispose of non-compliant vehicles, the organisation said.

Nearly £70m was paid to the owners of more than 36,000 cars and motorbikes, while £116.5m was handed to almost 18,000 van and minibus owners.

The scrappage scheme offers drivers in London payments of up to £1,000 for a motorbike, £2,000 for a car and up to £7,000 for a van or minibus, or for small businesses using the scheme. Charities can receive up to £9,000 to scrap minibuses.

The idea for TfL making donations of vehicles to Ukraine possible was first put forward by Richard Lofthouse, a former academic who works in communications, last year after he bought a non-Ulez compliant Ford Ranger and drove it to Ukraine.

It was then taken on by Kyiv’s mayor, Vitali Klitschko, who wrote to Khan to say some of the vehicles being scrapped, particularly 4x4s, had “enormous potential” to help the country in a “variety of life-saving and transport roles”.

However, Khan initially knocked back the request, on the advice of lawyers, arguing that the plan did not meet a legal threshold to demonstrate the benefit to Londoners.

Khan’s decision drew criticism, and the mayor, and former defence secretary Ben Wallace, later wrote to the government asking to give them permission to open the scheme up.

The then transport secretary Mark Harper responded in January, declaring that there was no legal barrier to the scheme going ahead, and by March the first drivers were able to donate their vehicles.

Under the general scheme, owners must show TfL a scrappage certificate to access money, while those who want to donate must get a certificate from the charity British-Ukrainian Aid.

After the closure of the scrappage scheme next month, those donating non-compliant vehicles to Ukraine will no longer be able to receive grants for their unwanted vehicles.

TfL said that 96% of vehicles in London were now compliant with Ulez emissions standards, compared with 90.9% in June 2023, two months before Ulez was expanded.

Khan said: “I am proud that the scrappage scheme – the biggest in the UK – has supported so many Londoners to switch to cleaner, greener vehicles.

“I’m also pleased that after the huge success of the Ukraine scheme, I’m planning to provide additional funding so that vehicles can continue to be donated to the country once the scrappage scheme closes.”

TfL did not say how much extra funding would be provided.