Paul Nuttall's office in Hanley, Stoke-On-Trent, appears to be defaced with red graffiti.
The Ukip leader and Stoke-On-Trent Central by-election candidate lost out to Labour candidate Gareth Snell by 2,620 votes on Friday.
ITV News Political Correspondent Carl Dinnen said Ukip would be "very disappointed" with the defeat.
"They thought they would run Labour much, much closer. It was a reasonably substantial loss", he added.
The vandalism comes days after Mr Nuttall apologised after he faced a storm of criticism over website posts that wrongly claimed he lost "close personal friends" at the Hillsborough disaster.
Labour have lost the Copeland by-election, a seat they had held since 1983, as the Conservatives edged the vote by 2,000 votes.Read the full story ›
Labour have held onto the crucial seat of Stoke-on-Trent, brushing aside Ukip leader Paul Nuttall in the process.Read the full story ›
The Brexit campaign made "false promises and false assurances, specifically designed to deceive", Labour peer Lord Livermore has claimed, adding he will oppose the Brexit bill.
The former adviser to both the Blair and Brown governments' claims came during the House of Lords second day of debating the Brexit bill.
Lord Livermore continued that the Government's "clear goal is an offshore small state Britain" that would mean less money for the NHS and a reduction in the rights of British workers, following the vote to leave the EU.
"I have no doubt this vision of Britain as a mid-Atlantic Singapore is strongly supported by hardline ideologues in the Conservative Party and in some sections of the media.
"But I equally have no doubt they would never have won the referendum had they been honest enough to articulate that beforehand.
"The verdict of the referendum has now become so distorted as to be unrecognisable...
"I believe that working people's lives will be made worse by this Bill.
"I believe that those who voted for Brexit in the greatest numbers will be those that suffer the most from the outcome."
As a result it was with a "clear conscience" that Lord Livermore said he would oppose the Bill and its "profoundly damaging effect on this country".
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