The Duchess of Cambridge made a surprise appearance at the Sarah Everard vigil on 13 March – and her visit has now elicited a response from Britain's most senior police officer, Dame Cressida Dick.
The Metropolitan Police Commissioner told BBC Radio 4's Today programme that Kate's visit was legal and that she had been "working", albeit it in a private capacity.
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She further noted that it was possible under the law to attend the event and that officers had allowed the March 13 vigil to continue for six hours without intervening.
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Ultimately, the police ended up clashing with protestors that evening – long after Kate had returned to Kensington Palace.
Referring to the royal's visit, Dame Cressida said: "She's in the course of her duties, she was working."
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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.
Kate paid a visit to Sarah Everard's vigil site on 13 March
"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."
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Kate's visit was not listed in the Court Circular – the daily list of royal engagements – suggesting it was not an official engagement. A private visit can constitute a royal duty, but it would still usually be included in the Court Circular.
Hundreds of floral tributes were placed in Clapham Common
The Commissioner 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.
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"You would have seen for six hours we did not enforce any laws, we showed some discretion and we allowed people to carry on.”
At the time of Kate's visit to the Clapham Common site, a royal source told HELLO!: "She obviously wanted to pay her respects to Sarah and her family.
A huge number of people paid tribute to 33-year-old Sarah
"She remembers being a young woman and walking around London at night before she got married. It struck a chord and she wanted to go and lay some flowers in person."
Sarah, who lived in Brixton, disappeared on 3 March after walking back from a friend's home in Clapham. Metropolitan Police officer Wayne Couzens, 48, was later arrested.
It was later revealed that the Duchess had sent a personal letter to Sarah's family expressing her condolences.
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