The PM tells the BBC he is concerned about the "cumulative" effect of marches on the Jewish community.
British Jews tell the BBC they are agonising over whether to stick to their usual routine this Sabbath.
A 19-year-old man is in custody and the Birmingham site has been searched.
Nuria Sajjad and Selena Lau died after a car crashed into the Study Preparatory School in July 2023.
Schoolchildren turn out to meet the monarch, with exotic birds and Bob Marley music all part of the welcome.