Critics of Boris Johnson have told BuzzFeed that the mayor of London is "weak on action and delivery", has often sidelined unpopular policies, and will leave the job without a legacy.
Since he announced last week that he wished to return to parliament, there has been a large amount of speculation that Johnson wants to become leader of the Conservative party.
The mayor appeared to confirm this when he admitted to The Sunday Times that he only applied for the mayoral job to "rapidly acquire administrative experience".
But Johnson will have to overcome a number of hurdles as he attempts to race to the top of the Conservative leadership, especially as his opponents paint a picture of an ambitious politician who thrives off popularity.
Valerie Shawcross, a Labour member of the London Assembly, said that while Johnson was particularly good as a spokesperson, he ignored policies that might not appeal to everyone.
"He's very good at the big speeches, at the PR, and he's very entertaining," she said. "At City Hall, he's a bit like the Cheshire cat – he'll just leave a grin. But he doesn't tackle big projects when there's a conflict. When it comes to big decisions, he backs off."
Shawcross described how Johnson cancelled existing plans to reduce air pollution in London, implementing a new one instead that would only come into place in 2020. "He gives you the impression that he's doing things when he's not," she said. "He doesn't want to offend particular interests."
She added that Johnson had failed to promote more women during his time as mayor. "He's got a reputation for not appointing women to senior posts," she said. "There's very few women in his administration who actually have a paid post. He tends to appoint women to do voluntary work, but the people who get the big salaries are all men."
Green party assembly-member Jenny Jones, a fierce critic of the mayor, agreed that he was wary of making unpopular decisions.
"Boris delegates," she said, "but not because he understands people's capabilities, but because he dislikes taking tough day-to-day decisions. He's not lazy, he works on other things, but the daily grind is not for him."
Jones added that the mayor would leave a disappointing legacy behind him. "After six years, [he] has failed to tackle the big problems London face – the cost of housing, insecure tenancies, air pollution levels that are a public health crisis, an unequal city where many are not paid the London Living Wage, the risks of climate change... He'll leave a legacy of failures."
But this view isn't accepted by everyone. Andrew Boff, the leader of the Conservative Greater London authority group, said Johnson has learned from his mayorship and would be better able to understand the impact of government policies.
"He's not making the same mistakes that he made when he started. I think when Boris came in he had little experience of local government, and he has learned a lot while he has been there and that's going to be very useful.
"Sometimes politicians who only ever talk philosophically find it difficult to think what effect policies have on Mrs Smith's leaking tap. Politics that you conduct at a high level can have a very granular impact. Sometimes politicians forget about those."
Boff also suggested that the mayor's leadership style is one that could position him well to lead a party. "Boris's style is a non-confrontational one, he's a great believer in building a consensus," he said.
"He's not somebody who's going to fight for an unpopular policy. He's going to be somebody who's going to be consensual in the way he conducts himself. And he has done to date. He's always tried to get a consensus on the London assembly between the different parties for the stuff that he's doing."
But despite this, Boff dismissed the idea of an imminent leadership campaign. He said: "We're not running the election right now, and there won't be a leadership contest for many, many years."