Home secretary says MPs must feel "safe and secure" while holding constituency meetings.
Early investigation has revealed “a potential motivation linked to Islamist extremism”, the Metropolitan Police said.
Labour MP Kim Leadbeater says her partner asked her to stand down following fatal stabbing of veteran Tory.
Two MPs have been stabbed to death in the last five years.
Boris Johnson said he was one of the “kindest, nicest, most gentle people in politics”.
The MP for Southend West was attacked while meeting residents at a church in Leigh-on-Sea.
The incident took place at his constituency surgery in Essex.
Official figures published on Friday suggest England's R rate has remained steady.
One person tweeted: "Does she not understand basics of UK parliament..."
From 24 October, fully vaccinated travellers returning to England will be able to take the quicker and cheaper test.