A Polish member of the European Parliament may be punished after he said that women should earn less than men because they are weaker, smaller and "less intelligent."

Janusz Korwin-Mikke, a radical right-winger who leads a marginal party, could face sanctions such as a reprimand, a fine or a temporary suspension.

An investigation has been opened under rules specifying that members must show mutual respect and refrain from "defamatory, racist or xenophobic language or behavior."

He said: "Of course women must earn less than men because they are weaker, they are smaller, they are less intelligent. They must earn less, that's all."

Spanish MEP Iratxe Garcia Perez angrily replied: "Look, according to your theory, I should not have the right to be here, as a member of this parliament."

Miss Garcia Perez, who is a member of the Socialist Worker's Party in Spain, continued: "And I know it hurts you, I know it hurts and worries you, that today women can sit in this house and represent European citizens with the same rights as you.

"I am here to defend all European women from men like you."

The European Parliament is now investigating the outspoken MEP for his comments.

Former Ukip leader Nigel Farage once said of the far-right firebrand: “I am happy that there is someone compared to whom I can look like a pretty moderate politician”.