The Telegraph has been forced to issue another correction to a Boris Johnson column, “clarifying” on the Conservative MP’s behalf a piece he wrote about a convicted drug dealer.

The potential future prime minister had used his £275,000-a-year column to criticise the case of Luke Jewitt, who had been allowed out of prison on day release to visit a spa with his mother.

In the column, Johnson described it as “yet another example of our cockeyed crook-coddling criminal justice system” and urged Telegraph readers to “fill yourself with righteous anger” at the sight of a man being allowed out of his cell while halfway through a nine-year jail term.

The newspaper has since corrected Johnson’s claim that Jewitt “was pushing huge quantities of cocaine and cannabis on to the streets”, following a formal complaint to the press regulator Ipso.

“Mr Jewitt was in fact cleared of charges relating to cannabis, and was convicted of conspiracy to supply 3kg of cocaine,” said the Telegraph in a correction added to Johnson’s article. “We are happy to clarify.”

However, the Daily Telegraph declined to remove Johnson’s description of the prisoner as “a kingpin of a sophisticated drugs importation and distribution network”, despite his family arguing he was a small part in a much wider £5.2m Essex drug-smuggling ring from which eight people were jailed.

Jewitt’s brother, the former Love Island contestant Jamie Jewitt, said his brother deserved to have been imprisoned for his crimes. “I’ll never defend him for what he’s done and nor will our family. It tore us apart emotionally and it was horrific,” he said.

However, he insisted Johnson had been “willing to twist facts and create an emotionally charged situation for his own gain”, given Jewitt was taking part in a government-approved release scheme designed to reintegrate him into society after four years behind bars.

“What Boris has done is he’s picked an opportunity to slander someone to use for his own reasons,” said Jamie Jewitt. “He’s tried to make it sound as though Luke wasn’t repentant and has shown no signs of remorse … It’s the most juvenile and childish way of reporting.”

While in prison, Jewitt won a debating competition for prisoners backed by Michael Gove and was chosen to discuss prison conditions with the justice secretary, David Gauke, during the Conservative party conference last year. He has also been a listener for the Samaritans and worked on mental health projects for fellow prisoners.

Jamie Jewitt also acknowledged the hypocrisy of the article, given recent confessions about youthful drug-taking by politicians.

He said Johnson had “picked out one of the few examples of people who have turned their life around and is looking to do good even after his sentence. He’s just picked the wrong person, he really has.”

A complaint earlier this year to Ipso forced the Telegraph to correct another Johnson column, in which he falsely claimed a no-deal Brexit was the most popular option among the British public.