The government has been accused of dragging its heels over efforts to extend blue badges for disabled drivers to carers of people with autism.
Blue badges were developed for people with serious physical disabilities
Lib Dem peer Lord Clement-Jones said a report had recommended the move in 2002, yet nothing had been done.
For the government, Lord Bassam said a review was under way and would report back in September.
But Lord Clement-Jones said: "The wheels at the Department for Transport are grinding extremely slowly."
The peer, who is also a trustee of the autism charity Treehouse, added: "The review was carried out by the Disabled Persons Transport Advisory Committee and reported in 2002.
"That means five years has now elapsed and the department is conducting a strategic review over the next few months."
Crossbencher the Countess of Mar urged the Department of Transport to use basic common sense.
"Anybody who sees a mother struggling with an autistic child or even a carer with an autistic adult will know just how difficult it is to get them to the shops," she said.
"They cannot travel in public transport. They cannot control them in order to walk long distances to the shops. Why can't they be given a blue badge?"
Labour peer Lord Ashley said people with autism could behave irrationally and sit in the middle of a road, because they were unaware of the danger.
"On any reasonable criterion, this kind of behaviour qualifies them for the blue badge," he said.
It is thought autism may affect as many as one in 100 children.
The developmental disorder affects the way people communicate and interacts with others.
For the government, Lord Bassam said the blue badge scheme was originally aimed at people with a serious physical disability, but there may be a case to extend it to other "newly understood" disabilities.
He admitted there were some delays after the first review mentioned by Lord Clement Jones, but said a strategic review would report back in September and any new policy would be determined by early 2008.
Asked why blue badges could not be handed out immediately to the parents and carers of people with autism, while the review is carried out, he replied: "I think it is right to conduct a proper strategic review."