The message from the Met Police came loud and clear - and very early in the morning. Hundreds of officers making over 100 arrests in dawn raids aimed at keeping trouble away from this weekend's Notting Hill Carnival.
Officers targeted suspected gangs, seizing cash and weapons. But today's high visibility raids were just one part of the operation -- police are keeping a close eye at what's going on online too, as Piers Hopkirk reports.
More top news
PC Keith Palmer will be remembered permanently at the National Memorial Arboretum, Home Secretary Amber Rudd has said.
ITV News rounds up the best pictures of the day as campaigners make a final stand before Theresa May triggers Brexit on Wednesday.
Demonstrators are gathering to march through central London towards Parliament Square, the scene of Wednesday's terror attack.