Boris Johnson will lead tributes to Sir David Amess in the House of Commons on Monday as debate rages about how drastically to step up security in the wake of the fatal attack on the Southend MP at his constituency surgery.

On Sunday night Amess’s family appealed for public unity, urging people to “set aside their differences and show kindness and love to all”. In a statement, his relatives said they were “absolutely broken” but had drawn strength from the tributes to him from across the political spectrum.

The attack sent shock waves through Westminster and reopened questions about MPs’ safety five years after the murder of Labour’s Jo Cox. The home secretary, Priti Patel, said on Sunday that she was considering offering MPs police protection at their surgeries, and the use of airport-style scanners was under consideration.

Asked how quickly such measures could be brought in, Patel told Sky News that all MPs were being contacted by their local police forces. “This isn’t a case of let’s wait for two weeks, three weeks, four weeks. These are immediate changes, and measures that are actively being put in place, and it starts with MPs.”