Boris Johnson pays tribute to 'global leadership' of Shinzo Abe following death
Mr Abe, 67, was shot from behind during a campaign speech in western Japan on Friday and later died in hospital.
The shooting prompted shock and sadness among politicians in the UK as the news emerged on Friday morning.
Mr Johnson’s predecessors were also among those paying tribute in the hours after the news broke.
Mr Johnson tweeted: “Incredibly sad news about Shinzo Abe.
“His global leadership through unchartered times will be remembered by many. My thoughts are with his family, friends and the Japanese people.
“The UK stands with you at this dark and sad time.”
Mrs May, who won the backing of Shinzo Abe for her Brexit deal after talks in the UK in January 2019, tweeted: “Truly heartbreaking to hear of the death of my friend Shinzo Abe, former prime minister of Japan — killed in the most appalling of circumstances while campaigning for his political party.”
Mr Abe visited London in January 2019, holding talks with Mrs May as she sought to get the backing of MPs for her Brexit deal.
David Cameron also called the developments “devsatating and shocking news”.
Sharing a photo of him shaking hands with the former Japanese premier, Mr Cameron said: “Shinzo Abe was a good friend personally, a strong partner to the UK, and a thoroughly kind and decent man.
“I enjoyed working with him.
“My heart goes out to his family and friends, and to the people of Japan at this very sad time.”
Mr Abe was Japan’s longest-serving leader before stepping down for health reasons in 2020.
Police arrested the suspected gunman at the scene of the attack, which shocked people in a country known as one of the world’s safest.