They ignored intelligence the address was linked to gun crime and went in anyway – but only found a small amount of the drug.

It was, Mr Donnelly said, an example of them “seeking to find cannabis they could use for their own purpose”.

Then, on May 15, Burns was tasked with checking out a tip-off about another cannabis farm at a house in Shrewton Road, Belle Vale.

Inside were six bin-bags worth, with a street value of around £32,000. He and French carried out the raid alone before they were joined by Bird – who was off-duty at the time but was called by the others.

Burns left the house with the drugs in an unmarked police Vauxhall Astra and drove straight to Brennan’s.

As the drugs were being unloaded, officers from the Professional Standards Department pounced, having watched everything unfold.

They caught them using mobile phone evidence and the trackers in the force cars they used.

Bird – a father-of-three and former undercover specialist – and Burns, of Ash Street, Southport, pleaded guilty to conspiring to supply Class B drugs. They were both full of remorse and shame, their defending counsel said.

French, of Lexton Drive, Southport, and Brennan were convicted after a trial. Both still maintained their innocence. Judge John Roberts told the former officers they had “soiled the good name of Merseyside Police” and “exploited your position and dealt in cannabis for your own commercial ends”. “It was a truly wicked thing to do,” the judge added.