Whilet he parent's point is correct, note that Nick Clegg is not and never was a EU civil servant (although he was a member of the European Parliament when the UK was still in the EU).
Whilst I know he was a curious example, he was obviously a high profile one.
According to the linked article he actually did work for the European Commission (part of the EU executive) as a civil servant.
"He took up a post at the European Commission in April 1994, working in the TACIS aid programme to the former Soviet Union. For two years, Clegg was responsible for developing direct aid programmes in Central Asia and the Caucasus worth €50 million. He was involved in negotiations with Russia on airline overflight rights, and launched a conference in Tashkent in 1993 that founded TRACECA—an international transport programme for the development of a transport corridor for Europe, the Caucasus and Asia. Vice-President and Trade Commissioner Leon Brittan then offered him a job in his private office, as a European Union policy adviser and speechwriter. As part of this role, Clegg was in charge of the EC negotiating team on Chinese and Russian accession talks to the World Trade Organization.[33]"
