My late wife Jo Cox was murdered in her constituency in 2016. The alleged attack on Helen Haines is a punch to the gut

Brendan Cox, the widower of murdered UK Labour MP Jo Cox (pictured), speaks at an event in London on 22 June 2016, on what would have been Jo’s 42nd birthday. Photograph: Justin Tallis/AFP/Getty Images

It’s never a good sign when you turn on your phone to find a dozen messages asking if you are OK. For reasons you will come to understand, I only get those messages when something awful has happened.

So on Monday, when I came out of an all-day meeting on antisemitism and picked up the messages from friends, I clicked across to check the news with real dread. The last time I’d received a similar barrage of messages was when former UK MP Ann Widdecombe was killed earlier this year.