McCann, who of course is still tormented by her own loss - the disappearance of her daughter three years ago - shared a sympathetic hug with Barry and Margaret Mizen on the steps of Westminster Cathedral.

The Mizens showed immense courage as they spoke of their ‘incredible pain’ at the service staged on the second anniversary of their son’s death and attended by Prince Charles.

Mrs McCann wept as Mrs Mizen described her last minutes with Jimmy and how she had always told him she loved him.

She was personally invited by Mrs Mizen because ‘they were both mothers who had lost their children'.

The Mizens called for more to be done to stop young people being murdered in the UK.

Jimmy was murdered the day after his 16th birthday, trying to avoid a fight, two years ago

Kate McCann is fast approaching the three-year anniversary of daughter Madeleine McCann vanishing on a family holiday to Portugal

At the service, led by the Archbishop of Westminster Vincent Nichols, the Mizen family spoke movingly of Jimmy.

Family members of murdered teenagers
Ben Kinsella, Rob Knox and Damilola Taylor
were also present.

They all met Prince Charles at a private reception afterwards.

Mrs Mizen said: ‘To all the mothers, take your babies and your children in your arms every day and tell them how much you love them.

‘We told Jimmy how much we loved him on his birthday the day before he died and he told us how much he loved us – it was a beautiful thing.’

Hundreds of relatives, school children, police and members of the public packed the cathedral for the service for peace.

The Archbishop urged politicians to set aside their differences in order to tackle youth crime.

He said: ‘As things stand detailed programmes of policies of each party do not fit together. Co-operation is needed if we are to progress.

‘Building a legacy of peace is something to which we must all subscribe. And even this weekend another young man, Marcin Bilaszewski, was stabbed to death in Finsbury Park – the eighth teenager to die in this way in the last six weeks.

We know that there is too much violence in our lives. We know there are too many knives on our‘ streets.

Prince Charles arrives at the service held in the memory of all young victims of knife and gun crime

We know there are too many injuries and deaths caused by them.

‘Building a legacy of peace involves change in all of us. Each of us has to be part of this legacy.’ 

Jimmy was murdered in May 2008 when he went out to buy a lottery ticket with his older brother Harry near their home in Lee, south east London.

He was celebrating having turned 16 the day before and the pair stopped at Three Cook's Bakery for something to eat.

While there, Jake Fahri – who had been cautioned by police several years earlier for harassing Harry – brushed past the brothers and the trio became involved in a scuffle.

Fahri, now 20, a heavy cannabis smoker and school dropout, tried to attack them with an advertising sign before hurling a glass dish at Jimmy.

It smashed into his neck, severing his jugular vein. The teenager died in his brother's arms in the shop and when his mother rushed to the scene, she fainted at the sight.

The Mizen family have set up a foundation in memory of Jimmy to prevent youth violence.