Kemi Badenoch has written a letter to voters in north-east Essex ahead of next week's by-election
Conservative leader Kemi Badenoch has vowed to "put forward a serious candidate" to run in a coastal by-election if a standards investigation leads to another one.
Voters in Clacton in Essex are due to go to the polls on Thursday after Nigel Farage stood down as an MP, triggering a by-election that he will stand in.
Reform UK's leader will be one of 34 candidates on the lengthy ballot paper, although Labour, the Conservatives, Liberal Democrats and Greens are not putting up candidates, claiming the resignation is a stunt with no bearing on the inquiry.
In a letter "to the people of Clacton", Badenoch wrote: "Nigel Farage has called this by-election not to help you, but to help himself."
Farage was being investigated by the parliamentary standards commissioner Daniel Greenberg over a £5m gift from cryptocurrency tycoon Christopher Harborne, which he received before taking his seat in the House of Commons.
The investigation was looking into whether he should have declared the money when he arrived in Parliament.
But it was suspended on his resignation and is likely to resume if he wins the by-election, which he is billing as a public vote on the issue of his honesty.
If he is found to have broken the rules and a suspension of more than 10 days is imposed, it could trigger a recall petition and the prospect of Farage losing his seat, forcing another public vote.
Nigel Farage, Reform UK leader, has now stood for re-election following his success in winning the seat in the 2024 general election
Badenoch wrote: "Mr Farage wants the people of Clacton to settle his problems for him.
"He wants to point to you and say, 'even after the £5m scandal, Clacton still chose me'.
"The people of Clacton are entitled to ask why someone would donate Nigel Farage that kind of money".
The Reform leader has said the money was an "unconditional gift".
Farage previously said the money was for his security, given to him "with the knowledge that the state in this country has never, ever wanted to help" with his personal protection.