WikiLeaks founder Julian Assange has been released from prison and left the UK after reaching a plea deal with US authorities.

Court papers filed by the US Justice Department show Assange is scheduled to appear in federal court to plead guilty to an Espionage Act charge of conspiring to unlawfully obtain and disseminate classified national defence information.

It followed the publication of hundreds of thousands of leaked documents relating to the Afghanistan and Iraq wars.

He will return to his home country of Australia after his plea and sentencing, scheduled for Wednesday morning local time in the Mariana Islands, a US commonwealth in the Western Pacific.

A plane carrying Assange left Stansted Airport on Monday before landing at a Bangkok airport for refuelling at around noon local time (6am BST) on Tuesday.

In a statement posted on X just after midnight on Tuesday, the official WikiLeaks account said Assange was granted bail by the High Court in London and released from Belmarsh Prison on Monday morning “after having spent 1,901 days there”.

The statement continued: “He was granted bail by the High Court in London and was released at Stansted airport during the afternoon, where he boarded a plane and departed the UK.

“This is the result of a global campaign that spanned grass-roots organisers, press freedom campaigners, legislators and leaders from across the political spectrum, all the way to the United Nations.

“This created the space for a long period of negotiations with the US Department of Justice, leading to a deal that has not yet been formally finalised.”

Video posted to X by WikiLeaks showed Assange, seated and dressed casually in jeans and a shirt, discussing the text on a sheet of paper.

He is then shown walking up steps onto a Vista Jet aircraft.

Speaking on Assange’s release, Australian Prime Minister Anthony Albanese told the nation’s parliament on Tuesday “we want him brought home to Australia”.

He said: “I’ve been very clear as both the Labour leader and opposition, but also as prime minister that – regardless of the views that people have about Mr Assange’s activities – the case has dragged on for too long.

“There is nothing to be gained by his continued incarceration and we want him brought home to Australia.”

Mr Albanese added that Australian diplomatic forces “have engaged and advocated Australia’s interest using all appropriate channels to support a positive outcome”, which he took up early in his role after being elected prime minister in 2022.

He added: “I will have more to say when these legal proceedings have concluded, which I hope will be very soon, and I will report as appropriate at that time.”

A letter to the United States chief judge of the District Court for the Northern Mariana Islands Ramona V Manglona, as seen by the PA news agency, also confirmed Assange intends to return to Australia once proceedings conclude.

The WikiLeaks statement also thanked “all who stood by us, fought for us, and remained utterly committed in the fight for his freedom”.

It said: “After more than five years in a 2×3 metre cell, isolated 23 hours a day, he will soon reunite with his wife Stella Assange, and their children, who have only known their father from behind bars.

“WikiLeaks published ground-breaking stories of government corruption and human rights abuses, holding the powerful accountable for their actions. As editor-in-chief, Julian paid severely for these principles, and for the people’s right to know.

“As he returns to Australia, we thank all who stood by us, fought for us, and remained utterly committed in the fight for his freedom. Julian’s freedom is our freedom.”

In a separate post on X, Mrs Assange said: “Julian is free!!!!

“Words cannot express our immense gratitude to YOU- yes YOU, who have all mobilised for years and years to make this come true. THANK YOU. tHANK YOU. THANK YOU.”

Assange’s mother, Christine Assange, told Australia’s Sky News that she is “grateful” her son’s ordeal is “finally coming to an end”.

She said: “This shows the importance and power of quiet diplomacy. Many have used my son’s situation to push their own agenda, so I am grateful to those unseen, hard-working people who put Julian‘s welfare first.

“The past 14 years have obviously taken a toll on me as a mother, so I wish to thank you in advance for respecting my privacy.”

Assange had been locked in a lengthy legal battle in the UK over his extradition, which saw him enter and live in the Ecuadorean Embassy in London in 2012 before his detention in Belmarsh prison.

In a January 2021 ruling, then-district judge Vanessa Baraitser said Assange should not be sent to the US, citing a real and “oppressive” risk of suicide, while ruling against him on all other issues.

Later that year, US authorities won a High Court bid to overturn this block, paving the way towards Assange’s extradition.

Assange was due to bring his own challenge to the High Court in London in early July after he was recently given the go-ahead to challenge the original judge’s dismissal of parts of his case.

Assange has been in custody at HMP Belmarsh for more than five years, fighting his lengthy legal battle against extradition to the United States.