Mr Justice Johnson, who jailed the 37-year-old marquess for failing to pay pounds 10,534 to his estranged wife Becky, said that he had been acting in excess of his powers when he imposed the sentence.
Sitting in Manchester, the judge said: 'I regard it as my duty at the earliest possible moment to order the discharge from prison of Lord Blandford. I shall make an order to that
Blandford was sent to Pentonville on Tuesday for failing to comply with the High Court order to pay the arrears.
The judge said he had asked for the case to be re-listed because he had anxiety about the sentence he had imposed.
Mr Justice Johnson said that when he imposed the order over the 'substantial' maintenance arrears amounting to more than four months' payments, he had asked counsel for both sides whether there was any limit to his powers and they had agreed the only limit was two years.
But later he had done some research and it had seemed to him the counsel had been in error.
Mr Justice Johnson came to the conclusion that the maximum he was allowed to impose was six weeks under the Debtors Act. He asked the Official Solicitor to re-list the case.
He said: 'I am satisfied the power of the court in these circumstances is limited to the imposition of a term of imprisonment of six weeks and accordingly my order was in excess of my jurisdiction.'
The marquess - heir to Blenheim Palace - who was arrested on Tuesday, was not in court to hear the ruling. During the hearing, Sara Staite, representing the marquess, called for his immediate release.
The Official Solicitor's counsel, James Mumby QC, had supported the argument that the judge had no alternative but to release Blandford.
It was opposed by Hugh Bennett QC, acting for Lady Blandford.
A prison spokesman said the marquess was released from Pentonville by the back entrance.Reuse content