The Supreme Court ruling that the fees charged for people to bring employment tribunal claims are unlawful will lead to an increase in the number of cases brought against charities, lawyers have warned.

In 2013, the government introduced fees of up to £1,200 for people to bring employment tribunal claims in a bid to reduce the number of spurious cases faced by employers. There was previously no charge for bringing a case.

The fees, which led to a dramatic fall in the number of claims dealt with by employment tribunals, were yesterday ruled unlawful by the Supreme Court after a challenge brought by the trade union Unison, which said they prevented workers from accessing justice.

William Garnett, a partner in the employment department at the law firm Bates Wells Braithwaite, said he thought the ruling would lead to an increase in the number of spurious “try-on” claims against charities.

“This is not great news for employers in the third sector,” he said. “The reason is that, arguably, people on lower rates of pay were disproportionately disadvantaged by the fees regime. The third sector has a lot of low-paid people.”

Garnett said charities might be seen as soft targets for employees trying to bring employment tribunal claims because organisations would be keen to protect their reputations and therefore more likely to want to settle cases.

“It is a sector that does get taken advantage of,” he said. “Of course there are a lot of genuine claims, but there are a lot of spurious ones also.”

Nick Le Riche, a partner in the employment team at the law firm Bircham Dyson Bell, agreed that the ruling would lead to an increase in the number of claims against charities and said the ruling might result in people trying to bring claims that were otherwise out of time.

They might argue that under the old fees structure they could not afford to bring the case in the time allowed, he said, and argue that the claim should be allowed in the new environment.

But both Garnett and Le Riche said they thought the government would try to reintroduce a new charging regime.

Garnett said the Supreme Court had not ruled that any fees were unlawful, just the fee structure previously implemented.

“This is not the end of the story,” he said. “I’m sure the government will be back with a new fees regime.”