Ibori was jailed in the UK for fraud totalling nearly £50m in 2012.
He was due to be released on 20 December but instead was held in immigration detention.
After he was released he launched his claim against the Home Secretary Amber Rudd for damages for false imprisonment and breach of his rights.
On Monday Mrs Justice Cheema-Grubb said the home secretary had been "wrong throughout her dealings with Mr Ibori over the weeks leading to his release" and that he had been unlawfully detained.
However, she rejected Ibori's claim for £4,000 in damages. Instead she awarded "nominal damages" of £1.
The judge also said that the decision to keep him in immigration detention was probably because of millions of pounds the authorities have still not recovered from him.
A Home Office email, published in the court judgement, recommended to keep him in immigration detention to buy time to work out how to recover at least £57m.
"The best course of action at present is to place him in immigration detention and review the position in February or when we know more about the confiscation process", it said.
On 21 December a High Court judge ordered his immediate release from prison. Ibori eventually left the UK in February.
Who is James Ibori?
James Ibori went from petty thief to Nigerian state governor to convicted money launderer. He came to the UK in the 1980s and worked as a cashier at a DIY store in London.
He was convicted in 1991 of stealing from the store but then returned to Nigeria and got involved in politics.
When he ran for Delta State governor he lied about his date of birth to hide his UK conviction - which would have prevented him standing for office.
He became governor in 1999 and soon began taking money from state coffers.
The British police began to take an interest in Ibori again in 2005 after they came across a purchase order for a private jet, made through his solicitor in London.
He evaded capture in Nigeria after a mob of supporters attacked police, but was arrested in Dubai in 2010 and was extradited to the UK.

Jamie Chapman, 28, of Tamar Drive, Smith's Wood, Solihull, is facing 15 charges and was remanded in custody at Birmingham Magistrates' Court.
Mr Chapman is due at Birmingham Crown Court on 9 December.
Police said there was no evidence to suggest any inappropriate contact between him and children at the nursery.
Officers are also liaising with previous places Mr Chapman worked at.
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A number of items of computer equipment were seized following a search of his home when he was arrested on Wednesday, the spokesman added.
Mr Chapman is charged with rape, four counts of causing or inciting a boy to engage in sexual activity, and two counts of causing or inciting the sexual exploitation of a child.
He is also accused of taking an indecent image of a child, distributing an indecent image of a child, and six counts of making an indecent photograph.

Joshua Bwalya, who was 16, was found dead in the street when officers were called to Movers Lane, Barking, at about 01:00 BST on Wednesday.
Det Ch Insp Gary Holmes of the Met Police said the attack was "a senseless act of violence" that "was not only cowardly, but brutal".
A boy, 16, and a man, 20, suspected of involvement were also injured.
Both were taken to different hospitals in the capital before they were arrested on suspicion of murder, police said.
The teenager has since been discharged and released on bail while inquiries continue.
The 20-year-old has also been discharged from hospital and is being held at a London police station.
A post-mortem examination of Joshua's body found multiple stab wounds were the cause of death.
Mr Holmes said: "I urge anyone who has information that can help our investigation to come forward and help us to bring Joshua's murderers to justice."
Convicted fraudster and former Nigerian state governor James Ibori has been awarded £1 ($1.30) for being unlawfully detained for 42 hours in the UK.
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A nursery worker has appeared in court accused of rape and inciting the sexual exploitation of a child.
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A teenage boy stabbed to death in a "senseless" and "cowardly" attack in east London has been named by police.