UKIP has suspended one of its MEPs, while an investigation continues into alleged financial irregularities.
UKIP has 10 MEPs in the European Parliament
Tom Wise, one of the party's 10 Euro MEPs, is being investigated by the European Anti-Fraud Office.
UKIP said "irregularities in his use of secretarial allowances" were being investigated.
But chairman John Whittaker said he hoped Mr Wise would be cleared, and the decision to suspend him should not be seen as prejudicing the outcome.
East of England MEP Mr Wise has been suspended from UKIP's group in the European Parliament.
The UK Independence Party said it would not be carrying out its own inquiry, but would await the findings of Olaf - the European Anti-Fraud Office.
Mr Whittaker told the BBC: "We're taking a principled stand. We have to be seen to be above suspicion. Any public body would suspend someone in a similar position."
He added: "Questions have been asked about this affair. Now that we've taken action, it should raise our standing." But he said he hoped the investigation would find that Mr Wise was not in breach of the rules.