Over more than five years, Ecuador put at least $5m (£3.7m) into a secret intelligence budget that protected the WikiLeaks founder while he had visits from Nigel Farage, members of European nationalist groups and individuals linked to the Kremlin.

Other guests included hackers, activists, lawyers and journalists.

In the lead-up to the US presidential election in 2016, his whistleblowing website WikiLeaks released several batches of emails connected to the Democratic party and Hillary Clinton’s campaign.

Last month, the Democratic National Committee filed a lawsuit against the Russian government, Donald Trump’s campaign and WikiLeaks, alleging a conspiracy to help swing the election for Trump.

Documents show the intelligence programme, called “Operation Guest”, which later became known as “Operation Hotel” – coupled with parallel covert actions – ran up an average cost of at least $66,000 a month for security, intelligence gathering and counter-intelligence to “protect” one of the world’s most high-profile fugitives.

An investigation by the Guardian and Focus Ecuador reveals the operation had the approval of the then Ecuadorian president, Rafael Correa, and the then foreign minister, Ricardo Patiño, according to sources.

Correa has defended the decision to give Assange political asylum and described the UK’s behaviour towards Ecuador as “intolerable”. Neither he nor the Ecuadorian government had any immediate comment.

From June 2012 to the end of August 2013, Operation Hotel cost Ecuador $972,889, according to documents belonging to the country’s intelligence agency, known as Senain.

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