Teenage gunman Sean Mercer was jailed for at least 22 years today for the murder of innocent schoolboy Rhys Jones.

Mercer, 18, blasted three bullets across a busy pub car park in Croxteth, Liverpool, targeting rivals who had strayed onto his turf.

But Rhys, 11, was shot in the neck when he wandered into the line of fire as he made his way home from football training.

He died in his mother’s arms a short time later.

Mercer, 18, was convicted of murder yesterday but the verdict could not be reported until now.

Following the convictions of his fellow gang members for helping him, Rhys’s father said: "Finally justice has been done for Rhys."

After almost four days of deliberations, the jury of seven women and five men convicted Mercer of murder unanimously.

What the jurors did not know was that just two months before he shot Rhys, Mercer was involved in a chilling rehearsal of the killing.

Waving a gun, he rode a motorcycle past members of the public on rival gang territory.

The incident was not reported to police at the time.

The jurors were also unaware that just weeks after shooting Rhys, Mercer was given a three-year Asbo for terrorising security guards at a sports centre.