The parents of Trayvon Martin visited a school in Central London today where they met with some black teenagers who would have been in the same year as their son.
The boys explained to them that the hooded sweatshirt, or 'hoodie', had been banned at the school.
Sixth formers, they said, are encouraged to wear suits, and the resulting change in people's attitude towards them has been remarkable.
"When I used to wear my hoodie, people didn't used to want to sit next to me on the bus", said one.
"I guess they thought I was a gangster or something. But in my suit, there's no problem. People even smile at me."
There's a heavy, transatlantic irony here.
There was bad weather on the night that Trayvon was killed, and he was wearing his hood up as he made his way home from the corner store - to stay out of the rain.
So in the campaign for justice that followed, the hoodie became a symbol of innocence - the 'million hoodie march' began.
One congressman even wore a hoodie on the floor of the House of Representatives.
Trayvon's mother thinks that in the end, her son's choice of clothing made no difference to his fate.
As she said to the boys gathered round her today, "you can change your clothes, but you can't change your skin."
The Martin family's sense of outrage comes from their firm belief that their son was killed, and the police failed properly to investigate his death, because he was African-American.
During their visit to the UK, they've been in touch with some prominent figures in the British black community, and they have discussed with them the damage that can be done when assumptions are made on the basis of skin colour.
It is a stark and sobering fact that if you are a black person in the UK then you are far more likely to be 'stopped and searched' by the police than your white counterparts.
The former England footballer Sol Campbell spoke to Trayvon's mum and dad about how 'stop and search' wears away the essential trust between a communtiy and its police force, and how the contamination of that relationship was one of the things that caused the riots which swept across Britain last summer.
The former chairman of the Commission for Racial Equality, Lord Ousley, told Trayvon's parents of how there are currently no fewer than 27 investigations of allegations of misconduct 'on the grounds of race' within the Metropolitan Police.
When he spoke of how to be sure of justice, the authorities need to be challenged, he wasn't talking about the situation in central Florida.
I was working in the United States when the 'Justice for Trayvon' campaign was beginning to gather pace.
Like many other British reporters on the story, I wrote knowingly about how, nearly half a century since the end of segregation, racial prejudice still lurks below the surface of American public life.
Since Trayvon's mum and dad have arrived in my country, I have been reminded that we are far from safe from it here.