Labour leader Ed Miliband has described Boris Johnson as a "good showman but not a very good mayor".
Speaking to ITV London, Mr Miliband said that while the London Mayor was a "fun guy" it was not enough to be a good Mayor.
However, the Labour leader insisted comedian Eddie Izzard - who has announced his intention to stand as London Mayor - was welcome to stand for Labour in the 2020 contest.
More top news
The 47-year-old man died shortly after 3pm on Tuesday.
Specialist explosive detection dogs searched through the town examining letter boxes and phone booths for signs of potential devices.
Temperatures reached 29.1C in St James's Park, central London.