A German regional court has acquitted an alleged neo-Nazi of a bomb attack aimed at Jews, with one lawyer describing the decision as “the worst legal mistake in the history of Dusseldorf.”

Ralf Spies, 52, was accused of having planted a pipe bomb at the Wehrhahn train station in the centre of the city in July 2000. Ten Eastern European immigrants – six of them Jewish – were injured in the attack.

Mr Spies was an original suspect soon after the bombing, but police felt they did not have enough evidence to arrest him at the time, AFP reported.

But he was briefly jailed for an unrelated offence and in 2014 a former cellmate told the police Mr Spies had boasted about carrying out the attack.

One of the injured woman lost her unborn child in the bombing and the cellmate said Mr Spies, who reportedly has a number of Neo-Nazi tattoos, had called this a case of “successful euthanasia.”

Other former prison mates also provided testimony against him, and taped phone calls appeared to show him boasting about the bombing. He was arrested in late 2017.

But during the trial a number of the witnesses withdrew their evidence, with the defence arguing that much of the testimony, coming as it did from prisoners attempting to plea-bargain, was not reliable.

The regional court released him from pre-trial detention in May due to "lack of sufficiently reliable testimony” and found him not guilty on Tuesday.

Mr Spies denied the charges against him.