The blue badge permit scheme was extended a year ago to include people with non-visible disabilities such as autism, dementia and anxiety.

But a BBC Shared Data Unit investigation reveals a "shocking disparity" between the approval rates of people with non-visible disabilities and those of people with physical disabilities.

In fact, scores of local authorities had lower approval rates for blue badge parking permits from non-visible disabilities applicants.

For ten councils the difference was so stark, it was more than 50 percentage points between the two types of application.

The Department for Transport(DfT) said it would review the impact of the new criteria.

The National Autistic Society said the BBC analysis revealed how important it was for councils to improve staff training to ensure they understood when people should be entitled to a "lifeline" blue badge parking permit.

Tim Nicholls, from the National Autistic Society, said a blue badge could facilitate journeys with a carer for someone with autism who may not be able to understand or react to the dangers of the road.

The permit could also help someone with autism overcome their anxiety over not finding a parking space or things going wrong on a trip, which could stop them from leaving the house entirely, he said.

People who had applied online also told reporters of the "trauma" of having to produce evidence of their disabilities to be scrutinised, and the difficulty of completing the form. In addition, they spoke of their reluctance to send original personal identity documents such as birth certificates in the post.

The removal of accessible parking bays next to shops and amenities "overnight, without any consultation" to allow for social distancing during the Covid-19 pandemic had also had a "massive impact" on disabled people, Scope said.

The BBC unit sent requests under the Freedom of Information Act and gathered responses via the WhatDoTheyKnow website from all of the 216 upper-tier councils in the UK.

They asked the number of parking bays they had designated for disabled people and how many blue badge applications each council had approved, directly refused or refused due an incomplete request from applicants for physical impairments and for applicants who applied under the non-visible disability criteria introduced in England in August 2019, over the 12-month period since.

They then calculated the approval rates for the two different types of application as percentages and compared them.

Across B&NES those figures came in:

155 badges for Applications for Blue Badges under "hidden disabilities" criteria approved since 30 August 2019.

14 Applications for Blue Badges under "hidden disabilities" criteria directly refused since 30 August 2019.

So in B&NES the situation is not as bad as in some areas of the UK with an approval of blue badges set as a percentage 59.39% - a difference of 14.7%.

People with non-visible disabilities, including anxiety disorders or a brain injury, were allowed to apply for a blue badge parking permit for the first time from 30 August 2019.

The Department for Transport said at the time of the change, this was "the biggest change to the scheme in nearly 50 years".

About 2.3 million disabled people in England currently have a blue badge, according to latest data.

The scheme was first introduced in 1970 to make access easier for disabled people.

It allows holders to park for free in pay-and-display spaces across the UK and for up to three hours on yellow lines.

109 of the 216 councils asked, were able to provide a breakdown of how they handled both blue badge applications for physical impairments and for people who applied under the non-visible disabilities criteria

Of those 109, 92 councils had higher approval rates for physical impairments applicants.

For 36 councils, the approval rate was more than 33.3 percentage points' higher for physical impairments applications . The difference was greater than 50 percentage points for ten councils.

Some 28,132 blue badges were issued to people with non-visible disabilities in England in the first 12 months of the scheme's extension.

Disabled parking provision

Guidance from the Department of Transport currently states that 5% of street parking be designated for Blue Badge holders. For car parks, the recommended level varies according to the main use of the car park and its size, but is between 2% and 6% of total capacity.

The BBC contacted the 10 councils with the largest difference in percentage points between the approval rates for applications under non-visible disabilities criteria and those for physical impairments. Those which responded to our questions were: Cumbria County Council, Portsmouth City Council, Durham County Council, Coventry City Council, Nottinghamshire County Council

James Taylor, executive director strategy impact and social change at disability equality charity Scope, said:

"This new data shows a shocking disparity between the allocations of Blue Badges to people with invisible and visible impairments. Our Helpline has also heard from disabled people with hidden impairments being denied a Blue Badge, for "not qualifying".

"This research highlights the urgent need for staff training of the decision makers in the councils, so they can recognize and understand the range of hidden impairment. Councils need also to understand the devastating impact their negative decision can have."

Tim Nicholls, head of policy and public affairs at the National Autistic Society, said: "These figures highlight the postcode lottery that has developed around Blue Badges. They reflect what we hear from autistic people and their families all the time. Too often important changes – like the ones that were supposed to mean more autistic people got a Blue Badge – often simply aren't being put into practice.

"Just leaving the house is incredibly hard for many autistic children and adults. Even a quick trip to the shops or park can involve detailed preparation. Some people don't understand the dangers of the road or are so anxious about things going wrong, like missing an appointment or the car park being full, that they can't contemplate going out at all.

"A Blue Badge can be a lifeline, helping you to get out and about in ways others take for granted. The changes to the rules last year were a big step in the right direction. But these figures suggest that people with non-visible disabilities, like autism, could be missing out. "

Councillor David Renard, transport spokesperson for the Local Government Association, which represents councils' interests, said:

"Councils want to make sure that local services and communities are as accessible as possible and they work closely with health professionals to ensure fair and robust criteria are used in the allocation of blue badges to local residents, including those with non-visible disabilities.

"Councils also have to try and strike a balance when making changes to their communities and places to ensure there are parking spaces available for everyone at all times of the day and we can keep traffic moving.

"With 10 million more cars on the road in the last 20 years, an increase of a third, this has become increasingly challenging for them."