Traffic police locked up a disabled grandfather for refusing to take a breath test - even though his medical condition made doing so impossible.

After being pulled over in Bradford, David Bradbury, pictured, repeatedly told officers that his poorly-functioning lungs meant he could not muster enough breath to activate their hand-held register.

But despite insisting he was happy to give a blood test - which later showed him to be under the drink-drive limit - the 56-year-old was locked in a cell for the night, leaving his disabled mother-in-law stranded in his car for two hours.

Today, the Disability Rights Commission, said Mr Bradbury might be able to pursue a legal case against the police under the Disability Discrimination Act.

As well as suffering from asthma and angina, Mr Bradbury has constricted ribs and chronic airways disease, forcing him to use three inhalers every day.

He said: "Basically, it means my lungs only have half the normal capacity which makes it very difficult for me to breathe."

Mr Bradbury, of Bishopdale Holme, Buttershaw, Bradford, had left the Little Horton Cycling Club in New Cross Street, along with his elderly in-laws when a police car pulled him over in nearby Gaythorne Road.

The former foundry worker had been drinking moderately and knew he was safe to drive.

"The police officer said they thought I had been drinking and I told him what I had.

"They told me to take a breathalyser test and I replied 'I cannot do it but I will try'".

Despite three attempts, Mr Bradbury failed to register a reading on the device.

"Then the officer told me 'You have refused to take a breath test so I am going to arrest you'".

He said: "I couldn't believe what was happening. I was being as co-operative as I possibly could but I just didn't have the breath to do it."

Because he was unable to get into a police van, officers drove Mr Bradbury's specially-adapted people carrier to the Bradford Central Police station. His wheelchair-bound mother-in-law Joyce Pickering and her partially-blind husband Leslie were left in the vehicle while he was taken inside.

"They told me to take a breath test on a machine there and once again I tried but failed to do it," said Mr Bradbury.

"I kept saying I was happy to take a blood test and that is what they did eventually."

But instead of then releasing him, Mr Bradbury was returned to a cell until the following morning.

"It was terrible. I couldn't sleep at all. They had to bring my support chair in because I was so uncomfortable.

"What was worse is that they left my mum and dad sitting outside in the car for two hours before they took them home. They wouldn't even let them use a toilet at the station."

Mr Bradbury added: "Officers came back to my cell three times for me to take a test, even though they must have known I couldn't do it."

And he said: "I told them I was claustrophobic but at one point they moved me from an open cell with bars on the front to a closed one. This made it even worse and I was in tears by that point."

At 8.40am - eight hours after his arrest - Mr Bradbury was finally released.

"To start with they said I'd have to walk to the bus stop but I told them I couldn't make it. In the end, officers lifted me into a police van and drove me back."

Two months after the incident, police called him to the station where they revealed the blood test had proven him to be under the limit.

"Although I knew it would prove this I am just relieved it is all over. I feel I have been treated really badly.

"All I wanted to do was sort it out from the start. I would never drive while I was drunk."

Alyson Rose, of the Disability Rights Commission, said Mr Bradbury should consider legal action against the force.

"This was a very unfortunate incident," she said.

"It shows that certainly the police need to look at their training and the way they approach disabled people. Many people don't realise that many disabled people have invisible impairments, like this man had.

"The DRC can provide advice for police forces or they might want to consult local disabled people on the best ways of learning lessons from this."

A West Yorkshire police spokesman said: "If we suspect anyone has been drink-driving we have a duty to stop them for the safety of themselves and other road users. If a driver is unable to provide a breath test they have to be tested by other means.

"Inevitably that means going to a police station and being asked to provide a blood sample."