Handing down the sentence to Mercer, the judge said it was "absolutely clear" that he had no answer to the case against him.

The judge said: "You proved you were a coward again. You did not admit what you had done, and the witnesses and Rhys Jones’s family had to go through a two-month trial.

"You engaged in a conscious effort to destroy the evidence which might lead to your detection, an effort which sucked in your co-defendants.

"I am quite satisfied you intended to kill one or both of the two young men from Norris Green, if you could do it without getting too close to them and putting yourself at risk.

"You shot at them, intending to hit them with a large calibre bullet.

"You then set about the systematic attempt to avoid being arrested, destroying evidence and pressurising witnesses.

"It is also true that your victim was young, and could be considered vulnerable, although anyone walking across that car park would have been vulnerable to what you did."

The judge said he considered that the fateful shooting of Strand gang leader Liam Smith in 2006 might have "encouraged'' Mercer.

The judge said: "Rhys Jones died as the trial of that murder approached. I have no doubt that you were well aware of that.

"The fact that another young man had been killed a year before did not make you hold back. It even may have encouraged you.

"Rhys Jones’s life is gone. We do not take a life for a life, although even if you are released, you will be under licence and supervised for as long as you live.

"The minimum period to be served is one of 22 years."

Accounting for Mercer’s time on remand, he will serve a minimum of 21 years and 122 days before he can be considered for release.