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.