Julian Assange’s lawyer says the WikiLeaks founder faces significant medical issues and possible extradition to the United States as he begins a “harsh”, 50-week jail sentence for breaching bail in the United Kingdom.

A British judge sentenced Assange to almost the maximum one year in prison on Wednesday night (Australian time) for skipping bail seven years ago when he fled to London’s Ecuadorian embassy.

Judge Deborah Taylor said it was hard to imagine a more serious version of the offence and said the 47-year-old Australian had exploited his privileged position to flout the law and express his disdain for British justice.

Assange’s lawyer, Jennifer Robinson, told The New Daily on Thursday morning that her client was having a “very difficult, tough time”.

“His health has deteriorated significantly. He had no medical treatment and exercise outside [the embassy] for six and a half years,” Ms Robinson said.

“He’s slowly getting the medical treatment he needs, but he’s really not well and I’m very concerned about him,” she added.

The white-haired Assange stood impassively with his hands clasped while the sentence was read.

His supporters in the public gallery at Southwark Crown Court chanted “Shame on you” at the judge as Assange was led away.

Julian Assange's sentence is as shocking as it is vindictive. We have grave concerns as to whether he will receive a fair extradition hearing in the UK.

— WikiLeaks (@wikileaks) May 1, 2019

WikiLeaks tweeted that the sentence was “as shocking as it is vindictive”.

Assange sought asylum in the Ecuadorian embassy in June 2012 to avoid extradition to Sweden, where he was wanted for questioning over rape and sexual assault allegations.

But it was the prospect of being “rendered” to the United States and fear he would be mistreated and possibly sent to the US detention camp for terrorism suspects at Guantanamo Bay.

American authorities have charged Assange with conspiring with former US Army intelligence analyst Chelsea Manning to break into a Pentagon computer system.

Sweden suspended its investigation into possible sexual misconduct against Assange two years ago.

“Our main concern is, and always has been, about US extradition,” Ms Robinson told The New Daily.

“There’s an initial hearing [Thursday UK time], but the US has 65 days in which to perfect the extradition provisional request that was served on Julian after he was arrested. So we have to wait to see what the final extradition request looks like,” she said.

Ms Robinson said the extradition case raised “fundamental free speech issues”.

“If you look at the actual allegations of the [US] indictment, it boils down to a journalist having communication with a source, talking to that source about what information they can provide, and having conversations with that source about how they might go about protecting their identity,” she said.

“It’s really a question about news gathering – which any good journalist can, and should, be doing in a protected way.”

Assange’s lawyer described his UK sentence as ‘harsh’. Photo: AAP

Ms Robinson said the Australian government could be doing more to help Assange.

“The Australian government could give Julian an assurance that he will not be sent to the US, which is what we’ve been asking them to do since 2010,” she said.

“Australia could be much more engaged and request him to be sent home to Australia. They haven’t done that. It’s a great concern that the Australian government is not taking greater steps to protect an Australian citizen.”

Assange was arrested on April 11 after Ecuador revoked his political asylum, accusing him of everything from meddling in the nation’s foreign affairs to poor hygiene.

Ms Robinson said Assange could expect to serve at least half of his 50-week sentence, with the rest on parole.

“Then it depends where we are on the extradition proceedings [as to] what will happen next,” she said.