Reform UK's Chief Whip Lee Anderson has joked that Angela Rayner received financial advice from Diane Abbott before she was forced to resign as Deputy Prime Minister.
In his speech, which was delayed when Reform adjusted its schedule to let Nigel Farage respond to Ms Rayner's resignation, he included a number of digs at Sir Keir Starmer's Cabinet.
Ms Rayner received the brunt of the criticism just hours after she admitted that she "did not meet the highest standards" when purchasing her £800,000 seaside flat in Hove.
The Ashton-under-Lyne MP, who has since taken "full responsibility for this error", was found by the Prime Minister's independent ethics adviser Sir Laurie Magnus to have breached the ministerial code by failing to seek further tax advice.
Despite Sir Keir expressing his sadness about losing Ms Rayner from his Government, Mr Anderson could not resist pointing the finger at warring Labour factions.
Ms Abbott, who served alongside Ms Rayner in Jeremy Corbyn's Shadow Cabinet, was mocked for her gaffe-prone interview appearances.
Mr Anderson said: "I’ve got to defend Angela Rayner, because I’ve been told by a good friend of mine that she did actually get sound financial advice, from her financial adviser, Diane Abbott."
The Ashfield MP was seemingly referring to some of Ms Abbott's most notable blunders, including when the then-Shadow Home Secretary suggested an extra 10,000 police officers would cost just £300,000.
Lee Anderson delivers his speech at Reform UK's annual conference
|PA
Ms Abbott, who was suspended from the Labour Party last year, had the whip suspended yet again after admitting she did not regret her remarks about Jewish people experiencing "prejudice" similar to Irish people and Travellers.
During his speech at the NEC in Birmingham, Mr Anderson also swiped at Ms Rayner's successor as Deputy Prime Minister, David Lammy.
Mr Lammy, who was once described by Mr Anderson as "Britain's village idiot", was demoted from the Foreign Office to take over from Shabana Mahmood as Justice Secretary.
Taking aim at Mr Lammy, Mr Anderson said: "David Lammy, Deputy Prime Minister.
Angela Rayner has resigned | PA"It seems that all you’ve got to do to become Deputy Prime Minister of this country is go on Mastermind and get every single question wrong."
Mr Lammy answered just five questions right in the general knowledge round of his appearance on the BBC quiz show in 2009.
The Tottenham MP thought that Red Leicester cheese accompanied port and that Henry VII acceded to the English throne after the death of Henry VIII.
During Mr Anderson's speech, Reform UK's Chief Whip expressed huge concerns about Britain's ballooning benefits system.
Diane Abbott is president of Stand Up to Racism | PAThe coalminer-turned-MP stressed that "benefits should be a safety net, not a career opinion".
He said: "The best way out of poverty is education, training, opportunities and a bit of decent graft.
"Benefits should be a safety net, not a career option. Work should always pay more than benefits, which is why Reform UK will overhaul our benefits system and reward our workers, not the shirkers."
Mr Anderson added: "We will let our young people know that they are the future of this great country."
Nigel Farage delivering his speech at the NEC | PAHowever, Mr Anderson was not the only Reform MP to blast Ms Rayner after her resignation.
Mr Farage warned that Sir Keir is at risk of facing factionalism comparable to the Tory Party's splits over Brexit.
He added: "The reason I have moved this speaking time forward is because this Government is deep in crisis.
"Not only have they fallen in deep unpopularity in just a year of winning the General Election, but it's becoming clear to all of us that it is a Cabinet of wholly unqualified people to run our country. They're not fit to govern."