A landlord said she was left facing a bill of thousands of pounds and with an office painted in light blue political colours after a tenancy dispute with Reform UK.
Tamsin May's property in Clacton was rented by the party in June before leader Nigel Farage's victory in the Essex constituency.
Mrs May expected to agree a five-year lease but instead the party left in August. She said rubbish was left behind and the keys were not returned.
Reform UK, which described the situation as regrettable, said it had now paid Mrs May the "just over £4,000" she paid to have the contract drawn up.