Australian WikiLeaks founder Julian Assange has spoken out for the first time from his London jail cell, saying his determination has not been affected by his incarceration.

In a world exclusive statement provided to reporter Mike Duffy, Mr Assange said the charges have only increased his purpose.

7News reports the mother of the WikiLeaks mastermind, Christine, has flown to London to be near her son, who is in solitary confinement inside Wandsworth Prison while he awaits an extradition hearing on Tuesday tonight.

"I told him how people from all over the world were standing up with placards and screaming out for his freedom and justice, and he was very heartened by that," she said.

In a ten-minute telephone conversation from inside the prison, 7News reports Christine asked the chief of one of the most controversial websites ever created “was it worth it?”

In a written statement, Mr Assange responded: “My convictions are unfaltering. I remain true to the ideals I have expressed. This circumstance shall not shake them.

"If anything this process has increased my determination that they are true and correct.”

American and other authorities have cracked down on WikiLeaks and Mr Assange since the site started publishing thousands of confidential US diplomatic cables that have embarrassed the United States and other parties around the world.

Despite this, Mr Assange’s biggest blast was saved for the world’s major finance companies who suspended payments to the not-for-profit site.

“We now know that Visa, Mastercard, Paypal and others are instruments of US foreign policy,” he said.

“It's not something we knew before.

“I am calling for the world to protect my work and my people from these illegal and immoral attacks.”

39-year-old Mr Assange, who created WikiLeaks in 2006, is in police custody in Britain after a European arrest warrant was issued by Sweden, which wants to question him about allegations of sexual crimes. He denies the allegations and will fight extradition.

He is also facing possible charges in the US over the embarrassing publication of the confidential cables, with Mr Assange’s British lawyer, Mark Stephens, claiming a secret US grand jury has been set up to work on charges that could be filed against the WikiLeaks founder in relation to the leaks.

Mr Assange’s mother Christine told 7News her support lies wholly behind her son and his cause.

“As a mother, I'm asking the world to stand up for my brave son."

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