Boris Johnson accused of politicising London Bridge knife attack

Political leaders and criminal justice campaigners have condemned the prime minister, Boris Johnson, for his response to the London Bridge attack in the wake of an article written for the Guardian by the father of one of the victims.

Jack Merritt, 25, coordinator for Cambridge University’s Learning Together initiative, which brings together offenders and those in higher education “to study alongside each other”, was stabbed to death by convicted terrorist Usman Khan on Friday, alongside 23-year-old Saskia Jones.

In a powerful piece published in the Guardian on Monday, Dave Merritt tackled head on Johnson’s response to the attack that took his son’s life, writing: “He [Jack] would be seething at his death, and his life, being used to perpetuate an agenda of hate that he gave his everything fighting against.”

Reacting to the article, the Labour leader, Jeremy Corbyn, said: “This morning I had the honour of meeting some of Jack’s friends. They were in total shock about the loss of Jack, who was clearly a compassionate and principled young man.

Related: 'Jack would be livid his death has been used to further an agenda of hate' | Dave Merritt

“Everything I hear about him, from his friends and this powerful and humane article from his father David, shows his determination to confront hate and injustice in our society and help bring communities together.

“We must learn from this tragedy and in Jack’s memory, protect people from these terrorist horrors but also build a world of greater peace and understanding.”

The article prompted a wave of support on social media, with many hailing Merritt’s bravery in the face of losing his son.

And it increased the pressure on Johnson over his response to the attack, after he was widely criticised by experts and on social media for appearing to blame Labour for the killings.

In the aftermath of the attack, which also injured three others, Johnson moved to blame sentencing regimes and automatic early release laws for the tragic incident.

Johnson used a lengthy interview on BBC One’s The Andrew Marr Show to accuse Labour of responsibility for the early release of Khan and to pledge that serious offenders would not be released early in the future.

On Monday, before the publication of Dave Merritt’s article, Johnson insisted he felt “a huge amount of sympathy” for the bereaved families.

But amid growing criticism of his stance, he added that he had been right to argue that the previous government’s decisions were to blame, saying: “I think any impartial assessment of the situation would concede that he was sentenced to a period in prison – 16 years, plus five years on licence – and then was subject to automatic early release having served eight years altogether.

“And I don’t think that was long enough in view of the gravity of his offence – which was to conspire to blow up the Stock Exchange and to cause other types of mayhem – and in view of the view that was taken of him by the initial sentencing judge, Judge Wilkie, and looking at what the judge had to say about him, it’s clear he was viewed as a very serious threat.”

Ed Davey, the deputy Liberal Democrat leader, accused Johnson of failing to understand the reasons for the attack. “Boris Johnson’s distasteful attempt to politicise a national tragedy is compounded by the fact he didn’t bother to properly understand the events that led to it,” he said.

“This is part of a pattern of behaviour, not concerning himself with the details and displaying total disregard for the families and victims involved. The similarity to his approach to Nazanin Zaghari-Ratcliffe and her family is striking. These are families experiencing the most awful situations and being utterly let down as Johnson blusters his way ill-prepared through his duties.

“Boris Johnson’s arrogant and blundering attitude is unacceptable at the best of times, but at times like these it is appalling.”

Before the article was published, Johnson appeared to defend himself from accusations of using the deaths for political point scoring.

Johnson told reporters: “I want to try to turn people’s lives around if you can. But you have to be realistic and what you must not have is a system of automatic early release and it was the automaticity that I’m afraid let us down here, because in the end the law had no choice but to let him out and then to hope that things would turn out well.

“I don’t think that was a reasonable expectation given what we knew about him.”

But his interpretation of what went wrong has been derided by experts in the criminal justice sector.

Andrew Neilson, director of campaigns at the Howard League for Penal Reform, said: “Much of the debate since has been distorted by the fact we are in the run-up to a general election.

“It is right that there should be a full investigation into what happened. Any such investigation should consider systemic issues and not simply sentencing policy or the decisions of individuals.

“Prisons in England and Wales are overcrowded and face record levels of violence and human misery. The probation service also faces well-documented problems. For years the Howard League has warned that such pressure is unsustainable.

“The answer does not lie in writing people off. The focus must be on safely fostering our human potential for change.

“It lies in a criminal justice system – and a wider response from other public agencies – that looks to solve problems, rather than making them worse. Whoever forms the next government should make this a national priority.”

Peter Dawson, director of the Prison Reform Trust, said: “All our experience shows us that policy decisions taken in the immediate aftermath of shocking events are likely to lead to unforeseen and unintended consequences.

“In criminal justice, those damaging consequences have sometimes lasted for many years, and done incalculable harm.

“We do not know all of the facts about Friday’s events and what led up to them. Attempting to draw conclusions in haste risks not only grave policy error, but also shows a lack of respect for those who have suffered most.”