The decision was made by Judge Moore after a member of the defence team was taken ill on Monday. The Judge had taken Thursday and Friday off sick last week himself and a barrister was unable to attend court this Thursday adding at least another week to the trial.
The continuous delays meant the case was set to head into a fifth week and possibly a sixth with jurors usually only expected to sit for two.
In a statement the defendants' solicitors said: 'The jury in the retrial of Alfie Meadows and Zac King at Woolwich Crown Court was discharged today. His Honor Judge Moore made the decision after a number of illness related delays in the proceedings.'
The decision means Meadows will no longer be represented by Michael Mansfield QC who had acted for him for the first two trials.
Meadows suffered a serious head wound during the march - that police described as life-threatening - after he was struck on the head with a police baton.
However, while King was arrested the following day, Meadows was not arrested until March the following year after the IPCC took up a complaint from him against the police.
The first trial at Kingston Crown Court saw several protesters acquitted, two pleaded guilty and the jury failed to decide on Meadows and King.
Proceedings at Woolwich Crown Court, which began on 29 October, have been beset by delays with the illnesses only the latest.
Other hold-ups were caused by the judge dealing with previous cases, efforts to fit witnesses in at convenient times and setting up video equipment to show evidence.
After recovering from brain surgery following the assault, being forced to drop out of university and enduring two long trials – one failing to reach a verdict and the other aborted – it has been a long two years for Meadows.
The former philosophy student was said to be too distraught over the decision after discovering his life would be put on hold for a further three to four months.
But Nina Power, a philosophy lecturer and activist who has supported Alfie throughout, said: “It's pretty depressing. It's going to be two and a quarter years by the time this is dealt with. It feels like just another punishment. It's as if they are sending out a warning message to others.”
Meanwhile dozens of supporters on social media called for the case to be kicked out with questions being raised over the cost and public interest in pursuing the trial.
According to the Crown Prosecution Service's own guidelines the public interest in holding a retrial depends on the seriousness of the offence, the length of time since the offence was committed, whether the defendant is in custody, the likely sentence if convicted and the consequences of not proceeding – for example on co-defendants.
It is rare for a case to be tried a third time with the CPS itself recommending against it, but with the second trial being aborted by the defence this would not apply.
Only recently the Crown dropped its racism case against PC Alex MacFarlane who was recorded telling a black suspect 'the problem with you is you will always be a nigger' following two hung juries.