UKIP MEP Gerard Batten had a brick thrown through a window at his London home in the early hours of Tuesday.
Mr Batten said he suspected it was part of an attempt by political opponents to intimidate UKIP candidates ahead of next Thursday's European elections.
"I don't know who did it but I have to deduce it is because of politics," he told BBC News.
Police are investigating the incident and have told the MEP they will step up patrols in his street.
Asked why he thought it was connected to his political campaigning, Mr Batten said: "It is odd that it has not happened to anyone else in the street. I am the only one involved in politics and there is an election going on."
He told BBC News it was the third time he had had a brick through his window - the other two incidents were in 2008. In the same year, Mr Batten said, he had disturbed a youth trying to smash his car window.
Describing Tuesday's incident, he said: "My wife and I were woken at 3.30am by a noise downstairs. On investigating we could see nothing out of place and went back to bed, assuming the noise had been caused by a household pet.
"We were woken 45 minutes later by a much louder noise, accompanied by the sound of breaking glass. On rushing downstairs, we discovered that a housebrick had been thrown through our living-room window. The police were informed and are currently investigating."
Mr Batten has been one of London's representatives in the European Parliament since June 2004 and in 2008 he was UKIP's London mayoral candidate.