The Workers Party candidate came third in the polls last Thursday behind Labour and the Conservatives.
Labour’s Kim Leadbeater won by a narrow margin of just 323 votes.
But Mr Galloway is not giving up without a fight, and today (Monday) his campaign manager James Giles revealed a High Court challenge was on the cards.
He said: “We met with our legal team last week and our case is being prepared as part of a petition to have the result set aside.
“They are preparing our case to be prepared very shortly – maybe in a couple of weeks.
“That is all in motion. We believe they are legally watertight.
“It will be a High Court matter – we hope to have it heard before a judge – and it will be the mother of all court cases.”
Mr Giles said there were multiple elements to the Workers Party’s challenge.
The most significant aspect is a claim that the Galloway campaign was damaged by an incident outside a local mosque during which Ms Leadbeater was verbally attacked for supporting LGBT rights.
Mr Giles said it had been suggested that Mr Galloway had laughed at Ms Leadbeater as she was being harangued by an activist, and that reports by the press and on social media had led some local voters to turn against the Galloway campaign.
“At no point we were laughing [at Ms Leadbeater],” he said. “But that had an impact on Labour getting the edge.
He added that the activist had been condemned by Mr Galloway.
“We have been very clear throughout that we condemned his behaviour,” Mr Giles said.
Another element involves a decision by Kirklees Council to remove Galloway campaign posters after warning they breached guidelines as the “imprint” – the information detailing who is printing the material, the promoter and the candidate – was found to be 50 per cent too small.
In relation to the “urgent legal challenge” announced last week on its action over election posters, a Kirklees Council spokesperson said: “As always, our team has worked really hard to deliver this election in the most efficient and professional way.
“There are formal channels available to anyone who wishes to challenge the process.”