The Court of Final Appeal ruled that people who are not actually at rallies cannot be prosecuted as principal offenders, though they may be held liable as accomplices.

The panel struck down the attempt to use the “joint enterprise” principle to indict secondary offenders in the same manner as primary offenders if they share a “common purpose”.

A criminal barrister said: “They’ve effectively raised the bar for the prosecutors — and maybe even stopped a flood of sweeping and hasty charges.

“That does not mean that the government won’t try to bring different charges though, after going back to the drawing board.”

The judges said that physical participation was a “centrally important element” in the crimes and should not be overridden by the principle of joint enterprise.

The principle “cannot be relied on to fix liability as a principal offender on a defendant who was not present and not acting as part of an assembly together with others so assembled,” the judgment stated.