What are the criteria?

The Criminal Practice Direction of the Lord Chief Justice states:

“The preferment of a voluntary bill is an exceptional procedure. Consent should only be granted where good reason to depart from the normal procedure is clearly shown and only where the interests of justice, rather than considerations of administrative convenience, require it.”

In R v Arfen 176 JP 682 QBD,

Mr Justice Nicol identified several circumstances that would justify granting leave, including if the dismissal was made without regard to a relevant statutory provision or judicial authority, or if there was a legal error, or if the crown had new evidence that made a significant difference to its case, or if the dismissal decision was made without a rational basis.

The results of the Hillsborough inquests are likely to be a significant component of the prosecution’s case.

Are there other considerations?

Duckenfield’s legal team is likely to argue that due to unfair news coverage and delays, he cannot have a fair trial. Commenting on the likelihood of the applications’ success would be pure speculation.