Nigel Farage faces a battle to remain an MP with the Tories set on reclaiming his Clacton seat if he faces a sleaze probe-induced by-election.The embattled Reform UK leader is facing growing questions over his financial affairs and is subject to a Parliamentary investigation over a £5million gift from Thailand-based party donor Christopher Harborne.At the weekend he was again reported to the Westminster sleaze watchdog over the support given to him by long-term associate George Cottrell.The Sunday Times reported that Cottrell, who has a fraud conviction in the United States, provided funding for staffing and security, and the use of a London townhouse.Critics have said that this should have been declared under Parliamentary rules, but Mr Farage has claimed he is the victim of an 'establishment hit job' and insisted he had committed 'no wrongdoing'.If the probe is ruled against the Reform leader and suspends him from the Commons for more than 30 days he would be subject to a recall petition by voters, which could trigger a summer by-election. A Tory source said: 'If a by-election in Clacton comes, we will be ready.'Mr Farage could face a challenge on his right flank, with Restore UK leader Rupert Lowe, a former Reform MP, vowing to throw 'everything' at winning as well, having come third in the Makerfield by-election. If the probe is ruled against the Reform leader and suspends him from the Commons for more than 30 days he would be subject to a recall petition by voters in Clacton, which could trigger a summer by-election