Julian Assange
A protestor marked the second anniversary of Assange's asylum in London's Ecuadorian embassy with this effigy in 2014.Graham Lanktree

WikiLeaks has published more than half a million secret documents from the Saudi Foreign Ministry to mark Julian Assange's third year of asylum in London's Ecuadorian embassy on 19 June.

The leak contains secret memos, cables and other documents from Saudi embassies around the world, including some "Top Secret" reports from the country's Ministry of Interior and the Kingdom's General Intelligence Services.

Assange is monitored by Met police around the clock, with guards and police trucks posted outside the embassy. Scotland Yard has told ITV that the total cost of the operation has reached £11m (€15.4m, $17.4m).

This number was pegged at £10m in early February, meaning every four months Assange is detained costs UK taxpayers an additional £1m.

"Assange can spend the rest of his life in our embassy in London," said Ecuadorian President Rafael Correa in a video interview, adding that "the problem can be easily solved if the UK offers him immunity. Sweden could have always had a deposition in our embassy in London."

Correra continued: "If we had a European refugee in a European embassy in Quito [the capital of Ecuador], if we were to keep him three years without letting him stay, we would be called dictators, fascists."

The former hacker sought asylum in the embassy in 2012 after facing extradition from the UK to Sweden, where he faces questioning from authorities around sexual assault allegations.

In 2014 Swedish authorities agreed to travel to London to question Assange, but on 17 June Assange claimed that a Swedish prosecutor cancelled the interview.

In the past a number of MPs have called on Sweden to foot some of the bill for the costs of policing him.

Assange refuses to travel back to Sweden for questioning, he has said, because of fears he will be extradited to the US, where former attorney general Eric Holder has said there is "an active, ongoing criminal investigation" against him.

In 2010 WikiLeaks became well known for leaking logs from the wars in Afghanistan and Iraq, as well as 250,000 State Department diplomatic cables.

Warrants issued to Google revealed late last year show the US is seeking to prosecute him for several serious criminal offences, including espionage, conspiracy to commit espionage and hacking.