The Metropolitan Police Commissioner has claimed Kate Middleton's visit to Sarah Everard's vigil was legal.
Dame Cressida Dick has said despite the gathering on March 13 in Clapham Common being deemed unlawful by the force, the Duchess of Cambridge "was working".
However, at the time, Kate had said she had gone in a personal capacity to pay her respects to the 33-year-old whose body was found days after she went missing while walking home.
Speaking on the Today programme this morning, Dame Cressida also said the Met was fully aware beforehand the royal would be in attendance.
But the results of an independent investigation into the police's handling published yesterday said the force were not pre-warned.
What do you think about what Dame Cressida said? Let us know in the comments
Her Majesty's Inspectorate of Constabulary and Fire and Rescue Services (HMICFRS) deemed the force to have acted appropriately, according to Tuesday's report.
Officers at the memorial had been widely criticised for being too heavy-handed after images and footage of the event were released, leading to the watchdog probe.
Asked if the force knew about the Duchess of Cambridge's visit to Clapham Common, Dame Cressida told Today: "The Met did know, absolutely, but of course we take all sorts of precautions to make sure that we don't unwittingly draw attention to visits like that."
Asked if her visit was legal, the Met's Commissioner replied: "I would imagine that, of course I have not asked her this question, but I think it's worth looking at ... just how strongly people felt, what she said about her attendance there.
"She's in the course of her duties, she was working."
She added: "At that point people had a whole series of potential reasonable excuses for being away from home, we didn't all have them.
"I've picked out one that may apply to her but, let's be clear, there was a very calm vigil to which she attended where lots and lots of people came."
The Commissioner went on to say the Met treated the vigil honouring the tragic 33-year-old, who died after going missing on a walk home, as an "unlawful" gathering.
She said: "It was clearly possible under the law for somebody who lived locally to walk as many did and lay flowers legally, there are other reasons why people might be in the area and they could have laid flowers calmly and peacefully, potentially legally.
"You would have seen for six hours we did not enforce any laws, we showed some discretion and we allowed people to carry on."
Dame Cressida added: "We knew that it would result in a mass gathering, we knew there would be large numbers, we knew who would come, we knew it would be unlawful.
"I had a great deal of contact both with City Hall at the most senior levels and with senior members of the Government."
She went on to say: "What I was saying consistently was this is likely to be illegal, if it is illegal and people do not disperse when they're asked to do so, we will use as much discretion as we can, we will encourage people, we will try to get them to disperse, but if they don't disperse we will end up arresting people."
