Not only has Dominic Cummings ¹ applied the derogatory noun kunlangeta to Boris Johnson ², but he also regularly refers to him as a shopping trolley, because, according to Cummings, Johnson is indecisive and veers all over the place on policy, like a shopping trolley.

¹ The British political strategist Dominic Cummings (born 1971) served as Chief Adviser to Boris Johnson ² from July 2019 to November 2020.
² The British politician, author and former journalist Boris Johnson (born 1964) has served as Prime Minister of the United Kingdom and Leader of the Conservative Party since July 2019.

For example, Dominic Cummings was reported as referring to Boris Johnson as a shopping trolley in the following from The Independent (London, England) of Thursday 27^th May 2021:

How much damage has the testimony caused Johnson?
Whatever his motives, Cummings shone a light on failings in government that would have otherwise remained in the dark
ANDREW GRICE

Dominic Cummings did not live up to the caricature of himself painted in the run-up to his marathon seven-hour appearance at the health and science select committees. […]
Instead, Cummings emerged as a credible witness […].
[…]
There was a catalogue of criticism of Johnson: Cummings regarded him as “unfit for the job” and it was “completely crackers” he had become prime minister. His most serious charge was that Johnson overruled his advisers to delay last autumn’s second lockdown. This matters because more people died in the second wave than the first. Johnson regarded the first lockdown as a mistake, Cummings said, viewing the economic damage as worse than Covid. He quoted Johnson as repeatedly saying he should have been the mayor in the film Jaws, who kept the beaches open even though a killer shark was on the rampage.
At the outset, Johnson dismissed Covid as a “scare story” like swine flu and, incredibly, even suggested he should be injected with the virus live on television by Chris Whitty, the chief medical officer. He said Johnson changed his mind 10 times a day and contradicted his own policy day after day; he was “like a shopping trolley” crashing from one side of the aisle to the other.

And, on Twitter, Dominic Cummings uses a shopping-trolley emoji to designate Boris Johnson—for example in the following tweet, posted on Thursday 25^th August 2022:

But, interestingly, it was not Dominic Cummings who first referred to Boris Johnson as a shopping trolley: it was Boris Johnson himself, before he had decided whether to back leave or remain in the United Kingdom European Union membership referendum of Thursday 23^rd June 2016. In The Sunday Times (London, England) of Sunday 21^st February 2016, Tim Shipman, political editor, concluded as follows an essay on where Boris Johnson was standing on the referendum:

The last word should perhaps reside with the man himself. He bumped into someone in Westminster recently and said: “I’m veering all over the place like a shopping trolley.” Which in a murky and confusing world has the merit of honesty.

However, the image of the shopping trolley had already been used in British politics. The following are two examples of this use:

1-: From Tories are veering to the Right like a broken trolley, Clegg tells Lib Dems, by James Kirkup, deputy political editor, published in The Daily Telegraph (London, England) of Monday 11^th March 2013:

NICK CLEGG has attacked Theresa May and other Conservatives pushing to change Coalition policies, accusing them of trying to “veer off to the Right like a broken shopping trolley”.
The Liberal Democrat leader told his party conference that senior Conservative ministers were trying to appease unhappy Tory backbenchers.
The Lib Dems will never allow Mrs May, the Home Secretary, to take Britain out of the European Convention on Human Rights, he said.
[…]
“The Conservative Party knows it needs to stay on the centre ground to have any chance of speaking to ordinary people’s concerns,” he said.
“But they just can’t manage it, no matter how hard they try. They’re like a kind of broken shopping trolley. Every time you try and push them straight ahead they veer off to the right hand side.”

2-: From Hughes, thorn in side of Coalition, is brought in as justice minister, by Matthew Holehouse, political correspondent, published in The Daily Telegraph (London, England) of Thursday 19^th December 2013:

SIMON HUGHES, the veteran Liberal Democrat MP and frequent critic of Government policy, has been appointed as a justice minister.
Mr Hughes, who has represented Southwark since 1983, is a leading voice on the Left of his party and voted against the Government on secret courts. This is his first ministerial job.
He is currently deputy leader of the Lib Dems and his promotion will trigger an election for his replacement. Jeremy Browne, the former Home Office minister who criticised his party for being like a shopping trolley that veers to the left, is a possible front-runner.