Mr Leffler participated in the accession negotiations and was the first Swedish “Antici,” responsible for policy coordination under the Permanent Representative in the work in the Council of Ministers. He joined the European Commission in 1996, becoming Head of the unit in the Secretariat General responsible for the coordination of relations with the Council of Ministers. From 1999 to 2002, he was the Deputy Head of the Private Office of the European Commissioner for External Relations, Chris Patten.