The protester jailed for disrupting the 2012 Oxford-Cambridge boat race has been ordered to leave the UK.
Trenton Oldfield, 37, has been told by the Home Office his presence in the country would not be "conducive to the public good", reports the Guardian.
Oldfield, who is Australian, has lived in the UK for ten years and his British wife is expecting their child this week.
Oldfield has appealed the decision
He had applied for a spousal visa but this has been refused.
Oldfield, whose British wife Deepa Naik is expecting a child, told the Guardian he had appealed against the decision.
He said: "No one was expecting this. I have a tier one visa, as a highly skilled migrant, and I was sentenced to less than a year.
"The lawyer said I had nothing to worry about because it was less than a year. It feels to me that this is a very vindictive decision, very political and very much an overreaction."
He added: "Before bringing their verdict, the jury asked the judge if she could be lenient. The probation officer recommended a non-custodial sentence.
"The sentence was excessive, but the judge also said I have contributed positively to life in this country."
A Home Office spokesman said: "Those who come to the UK must abide by our laws."
Oldfield made headlines last April when he purposefully swam in the path of the boats in the historic annual race.
The competition was halted for half an hour as he was hauled out of the river before being arrested and charged with a public order offence.
He was jailed for six months, a sentence many thought unnecessarily severe. He was released with an electronic tag after seven weeks.
Oldfield after being pulled from the Thames
The Australian claimed he was demonstrating against "elitism" but received heavy criticism when he attempted to justify his argument in a disastrous radio interview with Nicky Cambell in December.
Sentencing Oldfield in October last year Judge Anne Molyneux said he had ruined the race for everyone.
"You caused delay and disruption to it and to the members of the public who had gone to watch it and to enjoy the spectacle of top athletes competing," she said.
"The rowers had trained for many months. You had no regard for the sacrifices they had made or for their rigorous training when you swam into their paths."
Adding that Oldfield's actions had endangered his life and those of others, the judge said: "Your offence was planned. It was deliberate. It was disproportionate. It was dangerous."
He later said he had no regrets over the incident.