The family of Lindsay and Craig Foreman, who have been detained in Iran since January 2025, are calling for the UK government to exchange Iranian convicted stalker Richard Jan for the pair.
Mr Foreman told Sky News that Iranian authorities had signalled their interest in Jan, who is serving a life sentence and has been dubbed the UK's "worst stalker", and his release could be used to secure their freedom.
On the proposed prisoner swap, Mr Lammy told Sky's Trevor Phillips: "Of course, arrangements can be made of that kind, but the specifics on this would not be right. And I'm not sure from what I've heard that this is… credible".
Mr Lammy, who is also the justice secretary, said he could not go into detail on their case because it would "undermine the discussions that we're having with the Iranians".
Ms Foreman's son, Joe Bennett, said he was hopeful there had been a "shift" in the UK government's approach to his mother and stepfather's case following Mr Lammy's comments.
"The question that we wanted to ask as a family is, if this isn't the solution or a proposed solution, then why not?", he said.
"Anything can be done in theory, but it's been a long time coming where it gets the attention it warrants.
"And the conversation to be had, at least we can either get a proposed path to their release or closure that this isn't a solution."
Richard Ratcliffe, whose wife Nazanin Zaghari-Ratcliffe was jailed in Iran for almost six years, said Mr Lammy's words were encouraging, and a prisoner swap should be on the table.
"It is welcome that David Lammy is making positive noises," he said.
"Of course, he is the secretary of state [for justice], so it is in his gift to review parole board decisions, it's in his gift to discuss with his colleagues and find a way."
He said that Jan's case had been raised as part of discussions to secure his wife's release so it was "not a surprise that he continues to be on the table".
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Sir Jeremy Hunt, who was the foreign secretary while Ms Zaghari-Ratcliffe was imprisoned in Iran, said the UK government should be doing "everything it possibly can" to free the Foremans but urged caution.
"Obviously, what you don't want to do is something that leads to the next person being illegally detained by the Iranians," he said.
"So you have to be careful that you don't reward the kind of absolutely despicable behaviour that we're seeing from Iran, one of the very few governments in the world that will arbitrarily detain an innocent person as a tool of diplomatic leverage."
The couple were travelling through Iran on a motorcycle trip around the world when they were detained by Iranian authorities on espionage charges.
Emergency crews were called to River Road in Barking at around 11.20pm on Saturday.
They found three men - aged 22, 23 and 28 - with stab wounds. All three were taken to hospital, and the 22-year-old remains there in a critical condition.
The other two were later discharged and taken into custody after being arrested on suspicion of attempted murder.
The 23-year-old became unwell in custody and was returned to hospital, the Metropolitan Police said.
Chief Inspector Mo Mahmood said: "Our thoughts are with the critically injured man and his family at this very difficult time.
"We understand the concern this incident will have caused for the local community and officers continue to work at pace to understand what happened."
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He said it was an "isolated incident" and police would remain in the area over the coming days.
"We know there were a number of people in and around the area at the time of the incident and are appealing for any witnesses or those with information or mobile phone or dash cam footage to please come forward," he said.
"No detail is too small."
It is understood there had been concern about online commentary and potential public disorder, so the police force sought the CPS's views on issuing a message telling people it would address questions once proceedings were complete.
Prosecutors advised the force it could risk impacting the "integrity" of the case against Vickrum Digwa.
Mr Nowak, an 18-year-old university student, was handcuffed by police as he bled to death after being stabbed in the street with a ceremonial knife.
Digwa told police he was the victim of a racist attack after he knifed Mr Nowak five times in Portswood, Southampton, on 3 December 2025.
He was convicted of murder and given a life sentence with a minimum term of 21 years in prison for stabbing the finance student with a ceremonial Pesh Kabz, a 21cm Indo-Persian dagger previously used in battles to pierce through armour.
Digwa claimed he carried the murder weapon for religious reasons. He was also carrying a kirpan, the small knife not usually more than six inches long, including the handle, which can be carried by Sikh men and women.
Anger erupted after police body-worn video was released which showed officers ignored Mr Nowak's pleas that he had been stabbed, and placed him in handcuffs moments before he became unconscious and subsequently died.
Eleven people have since been charged after violent clashes at protests following the sentencing.
It is understood the statement contained information about the process of a court case, reminded people that nothing could be published that could prejudice legal proceedings, and said that police would answer questions once the trial was complete.
A Crown Prosecution Service spokesperson said: "The CPS highlighted to the police that protecting the integrity of the ongoing trial was essential, and of the risks of referring to any aspect of the evidence before it had been heard by the court and the case had been summed up by the judge to the jury.
"However, it was made clear that whether a statement was released was ultimately a police operational decision."
A spokesperson for Hampshire Police told Sky News: "Following the opening of the trial and the media reporting that followed, a significant amount of mis and disinformation was circulating online.
"This included requests for information to be shared that had not been fully examined as part of the murder trial.
"The intention of the statement was to remind the public that there were ongoing legal proceedings and that the law is clear that nothing could be published which could prejudice the trial.
"The decision not to publish was taken following advice from the CPS."
The Independent Office for Police Conduct (IOPC) is investigating Hampshire and Isle of Wight Constabulary's response in Mr Nowak's case.
The National Police Chiefs' Council is reviewing language used in anti-racism guidance following suggestions it may have influenced officers' actions on the night Mr Nowak died.
A jury inquest next year will also examine the circumstances surrounding Mr Nowak's death.
The attorney general is considering whether Digwa's sentence should be referred to the Court of Appeal under the unduly lenient scheme after receiving several requests.
Mr Nowak's father Mark has said the family "do not want his death to be used to create further division, hatred or tension", but the police's treatment of the student has sparked a political row in Britain and across the Atlantic.
Prime Minister Sir Keir Starmer has urged politicians to heed the teenager's relatives' calls not to use the case "to cause disturbances", while Reform UK leader Nigel Farage has been criticised for saying people should respond with "pure, cold rage".
Conservative leader Kemi Badenoch has called for a rapid review into the circumstances surrounding Henry Nowak's murder.
"The problem is not institutional racism towards blacks or whites but institutional incompetence," she wrote in The Sunday Times.
Downing Street has also hit out at US tech billionaire Elon Musk, accusing him of trying to "whip up division" after he said he was willing to fund a private prosecution against Hampshire Police.
US vice president JD Vance called for "righteous anger" and blamed Mr Nowak's murder on immigration.
Deputy PM and Justice Secretary David Lammy revealed to Sky News on Sunday that he told Mr Vance during a phone call on Saturday that he was "wrong" about the Henry Nowak case.
Mr Vance, who is good friends with Mr Lammy, blamed "the politics of self-hatred and the mass invasion of migrants" for his murder in a post on X.
Speaking to Sky's Trevor Phillips, Mr Lammy said: "I spoke to the vice president yesterday, and I wanted to emphasise a number of things.
"The first is that our democratic process is working well. This young man has been convicted. There is an investigation into the police by the Independent Police [Conduct] Authority. There is an investigation into Hampshire Police by the inspectorate. The [attorney general] is looking at the sentencing in relation to this. The national police chiefs are looking at the guidance in relation to this.
"The second thing was I disagree with him. This has got nothing to do with mass migration. This young man was a Brit. Let's be clear about that.
"And I said, "Look, Mr vice president, you're wrong about this.
"And it's also the case that actually murder is coming down in the United Kingdom. So we had an agreeable conversation. But we disagree."
Kim Yo Jong, who holds two senior roles in her brother's government, said North Korea will not tolerate any threat and branded the US push to denuclearise the country an "anachronistic dream", state media agency KCNA said.
Her remarks came ahead of Chinese President Xi Jinping's visit to North Korea for a summit on Monday, marking his first trip to the country in nearly seven years.
Ms Kim said US claims that Mr Xi and Donald Trump had confirmed a goal to denuclearise North Korea during a May summit were "false", adding that it "has the most accurate information" regarding the claims.
"The policy of continuously strengthening self-defensive nuclear war deterrence, as declared by the head of state, is an irreversible and final conclusion that must be executed unconditionally," she said.
She added: "Some officials in the US have failed to wake from their escapist and anachronistic dream".
Early this week, North Korea unveiled a new nuclear material production factory where its leader Mr Kim called for an "exponential" expansion of the country's atomic arsenal.
Analysts said the new uranium-enrichment site appeared aimed at reinforcing North Korea's negotiating position ahead of the summit while justifying an acceleration of its nuclear build-up.
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Mr Kim also visited a major munitions factory and ordered the country's missile production capacity to be increased 2.5 times over the next five years, Yonhap News Agency said on Sunday, citing North Korea's state newspaper, The Rodong Sinmun.
North Korea has been focusing on enlarging its nuclear arsenal diplomatic talks with Mr Trump collapsed in 2019.
Experts believe Mr Kim wants international recognition as a nuclear state so that he could demand lifting of international economic sanctions on North Korea.
Mr Xi's visit comes as Beijing seeks to strengthen its ties with Pyongyang, China's only formal treaty ally.
Ms Kim is often seen by her brother's side at military demonstrations and meetings with foreign leaders.
The teenage daughter of Kim Jong Un, thought to be named Kim Ju Ae, is also frequently pictured by his side at military events, and is thought to be being positioned as his successor.
Robert Evans Jr, 25, admitted manslaughter, while his father Robert Busby Evans, 47, and his uncle Barry Evans, 54, admitted being accessories for helping him flee.
Sharif Rahman, 44, died in August 2023, a week after an altercation outside his Indian restaurant in Owen Sound, Ontario.
A court heard the trio had tried to leave without paying a $145 (£78) bill and Evans Jr threw the punch that ultimately killed Mr Rahman, who had a wife and young daughter.
Barry Evans is said to have told his nephew to "run, run" and driven him away from the scene. His father, meanwhile, allegedly booked him a ticket back to the UK.
The three men - who are believed to be from Manchester - were extradited to Canada from Scotland late last year and pleaded guilty on Friday.
Under a plea deal, the older men were sentenced to time already served and will be deported, Canadian Broadcasting Corporation (CBC) reported.
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The broadcaster said neither man could read or write so their statements expressing regret were read in court by their lawyers.
Evans Jr will be sentenced for manslaughter on 10 July and CBC said he had told the court he's "sickened" by his actions and prays nightly for Mr Rahman's family.
The judge must now consider a defence argument that he should only spend another eight months in custody.