Gloucestershire and Somerset county councils failed to take into account the needs of the most vulnerable in society when they announced plans to withdraw funding from local libraries, a court has heard.

On the first day of a judicial review, both councils were accused by anti-cuts campaigners of neglecting their responsibilities to the elderly, the poor and the disabled in their rush to make budget savings. The case is being watched closely as it could be the first time a judgment is handed down in a legal challenge to library closures under the coalition.

Speaking for the claimants, Helen Mountfield QC said the councils had failed to comply with the Public Libraries and Museums Act of 1964, which obliges authorities to provide a "comprehensive and efficient" library service, and with public service equality legislation, meaning they had failed to properly establish whether certain sectors of society would be disproportionately affected by the cuts.

"If, say, you have to walk three miles to a library it's particularly disadvantageous to pre-school children, it's particularly disadvantageous to disabled people," she told the high court sitting in Birmingham. She argued that the authorities had failed in their duty to guard against indirect discrimination. They had also failed, she said, to carry out a thorough consultation with local communities.

"We weren't ever listened to so it's good that the politics is out of it now and it's being scrutinised according to the law," said Johanna Anderson, founder of Friends of Gloucestershire Libraries (FoGL) and one of a dozen campaigners who had travelled to Birmingham for the hearing.

John Irven, treasurer of Watchet Library Friends, said he and others in the Somerset town had been outraged over plans to withdraw funding from the local library.

"We would say we're a whole cross-section of people: young, old, middle-aged, retired," he said. "We're not against cuts per se. We just believe we can organise the service more efficiently – make cuts and still keep libraries open."

Tens of thousands of people across both counties signed petitions protesting against proposals, unveiled in February, to withdraw funding from at least 10 libraries in Gloucestershire and 11 in Somerset. The plans have been suspended pending the result of this week's judicial review.

The councils have appealed for volunteers to come forward to run certain libraries, an idea FoGL has condemned as "unfair and misguided". It predicts that a further seven libraries will close in Gloucestershire for want of partners to help co-fund the services. In both counties, many remaining libraries will have reduced stock, staff and opening hours.

James Goudie QC, for the defence, will make his submission to the court on Wednesday. He is expected to argue that the councils had taken the decision to cut funding to library services with great care and that the claimants' arguments should be dismissed.

Mr Justice McKenna could give a verdict in the review as early as Thursday. A verdict has not yet been returned on a judicial review of Brent council's proposed closures held in July.