McCanns defend £11m spent investigating Madeleine's disappearance as 10th anniversary approaches

Speaking about why his family had vowed to do “whatever it takes for as long as it takes” to find her, Gerry McCann said that anyone whose child had been abducted overseas would think it “reasonable” that everything possible was done to find them.

Last month the Home Office confirmed £85,000 was being given to the UK-based Metropolitan Police inquiry to cover operational costs from April to September.

It brings the total spent on the inquiry to date to £11 million.

Scotland Yard said last week that officers were still pursuing “critical” leads to trace Madeleine, who was aged three when she vanished from a holiday apartment in Praia da Luz in Portugal on May 3, 2007.

During an interview marking the upcoming anniversary, Mr McCann said it was right to bring resources to bear to investigate criminal acts carried out against Britons abroad.

“I think some of that criticism is really quite unfair actually, because I know it’s a single missing child, but there are millions of British tourists that go to the Algarve, year-on-year, and essentially you’ve got a British subject who was the subject of a crime,” he said.

“There were other crimes that came to light following Madeleine’s abduction, that involved British tourists, so I think prosecuting it to a reasonable end is what you would expect.”

Mr McCann, 48, added: “Others within law enforcement have made it very clear, this type of stranger abduction is exceptionally rare actually and we need to put it into perspective and it’s partly why Madeleine’s case is attracting so much attention, thrown in with many other ingredients, but this type of abduction is exceptionally rare.”

Around 30 British detectives were working on the UK side of the investigation into Madeleine’s disappearance, known as Operation Grange, when it was established in 2011.

The team, which has looked at more than 600 individuals so far, has now been scaled back to four detectives.

Speaking to the BBC’s Fiona Bruce, the couple, from Rothley, Leicestershire, said they had taken heart from the “real progress” which had been made by the Metropolitan Police.

Mrs McCann, 49, said: “It might not be as quick as we want, but there’s real progress being made and I think we need to take heart from that.

“We just have to go with the process and follow it through – whatever it takes for as long as it takes. There is still hope that we can find Madeleine.”

Asked how he and his wife were coping, Mr McCann said: “I think we’re doing a new normality really, particularly over probably the last – and it seems like a long time saying it – but over the last five years.

“Since the Metropolitan Police started their investigation, it has taken a huge pressure off us.

“After the initial Portuguese investigation closed, essentially, no-one else was actually doing anything proactively to try and find Madeleine. And I think every parent could understand that what you want – and what we have aspired to – is to have all the reasonable lines of enquiry followed to a logical conclusion.”

Mrs McCann, a former GP who has now returned to work in another area of medicine, added: “My hope for Madeleine being out there is no less than it was almost 10 years ago.”