MONSTER Aaron Campbell is being guarded round the clock in prison — as insiders revealed he’ll be a “marked man to his dying day”.

Jail sources told how the caged beast is shadowed by two security officers to protect him from fellow cons who are desperate to make him pay for his sickening crimes.

And they reckon revolted lags will be willing to bide their time to get their hands on Campbell, 16 — facing life behind bars for raping and murdering six-year-old Alesha MacPhail in Rothesay, Bute, last July.

One insider said: “The inmates are absolutely sickened by what he’s done. People know they could make a real name for themselves if they get to give him the doing of his life.

“It’s a waiting game. One day someone will get him. He’ll be closely protected and watched at the moment, but there’ll come a time when he’s by himself — and that’s the moment someone will get him.

“The guards do what they can to stop attacks, but people can be very inventive and cunning in this kind of environment. Campbell is a marked man and will be to his dying day.”

The fiend, currently being held at Polmont Young Offenders Institute near Falkirk, is also being monitored in case he tries to harm himself.

It’s understood he’ll undergo assessment to establish how risky his position is inside the jail.

Our source said: “Officials need to make sure prisoners are safe from themselves and from others.

“It is potentially possible that you could get officers dedicated to him. It’s entirely possible that that could happen.

“When somebody comes into custody, they have an assessment to determine what supervision level they would need.

“There’s a whole different range of measures depending on what the assessment comes out with. If that’s what’s required, then there would be measures in place to make sure that happens.”

A hearing last week to decide whether warped Campbell could be unmasked as Alesha’s killer heard threats had been made against him.

Defence QC Brian McConnachie told the High Court in Glasgow: “He has yesterday received information, warning or something about there effectively being a price on his head.”

But the lawyer added: “The word yesterday was that it was credible, but it now seems to be a different situation.”

Judge Lord Matthews — who had described the case as “one of the wickedest and most evil crimes in the history of this court” — agreed to lift the ban on naming and picturing Campbell.

It was a landmark decision in Scotland, where the law had prevented under-18s from being identified.

Campbell is due to return to court to be sentenced on March 21.

But legal insiders warned he could be eligible for parole in “as little as 15 to 17 years”.

One lawyer said: “Efforts, rightly or wrongly, will be made to readjust him. He has the prospect of always having to watch over his shoulder.”