Relatives of missing Ben Needham, from Sheffield, may take legal action to force the Government to make a decision about giving funding to South Yorkshire Police to help the search.
Ben was 21 months old when he vanished from the Greek island of Kos in 1991 while he was playing outside a farmhouse his grandparents were renovating.
Earlier this year, South Yorkshire Police asked the Home Office for financial help to pay for detectives to follow up new lines of inquiry but a decision has not yet been made.
Now the family has engaged human rights barrister Ian Brownhill, who spotted their plight on their campaigning Twitter feed and offered his services for free.
He said one option available is to go to the High Court to obtain an order to force the Home Office to make a decision.
The barrister added: “It’s effectively a power whereby the court can review the legality of something the Government or a public authority is doing, and we would effectively go along to the High Court and say it’s not fair, it’s not legal that the Needham family, and indeed Ben Needham himself are waiting for an answer on this funding.”
Mr Brownhill said he plans to write to Home Secretary Theresa May to ask her to make a decision.
Ben’s mother Kerry, 42, said there are huge differences in how the case of missing British girl Madeleine McCann is being treated compared to the disappearance of her son.
“We have seen what is available for one family of a missing child, and we have had nothing like that, nothing at all, even though there is all these comparisons between the two cases. And we’re still getting nowhere and I ask why?” she said.
His sister Leighanna, 20, added: “It seems like a never-ending game. We’ve not had any help in 23 years.”
In 2012 the Home Office backed a South Yorkshire Police operation when land was excavated on Kos.