It comes after recent speculation over potential changes the government could make to bring down the cost of the scheme in the Budget.
The number of people with a Motability car has increased sharply in recent years, to 860,000. Many of the cars leased by the scheme are adapted to be accessible for wheelchair users.
Higher-end vehicles account for about 50,000 of the vehicles leased by the scheme, with customers paying the additional cost for a premium vehicle using their own money.
Motability has long argued that the scheme provides a lifeline to disabled people.
But, as well as concern over the growing number of people accessing the scheme, some critics have said customers should not be able to get a “premium” car subsidised by the taxpayer.
Speaking earlier this month, Heidi Alexander, the transport secretary, said she would be “comfortable” with removing “really high-end cars” from the scheme.
Earlier this month, Farah Black, a disabled woman in Northern Ireland, spoke to the BBC about leasing a BMW on the Motability scheme.
She was unable to drive at all for 12 years after a serious injury, which led to life-threatening sepsis and the amputation of her leg.
She said she cried when she picked up her BMW, which is adapted for her needs as a wheelchair user and which she paid the additional cost for as an advance payment.
“We should all have a choice,” she said.
“Just because I’m disabled – why can I not have a choice and drive what I want?”