The European Commission says member states should drop restrictions on workers from the newest members in the light of evidence that the legendary Polish plumber and his colleagues have had a positive impact on the economies of their host countries.

The research, presented to the European Union parliament in Strasbourg on Tuesday, shows that free movement helps satisfy labour and skills shortages. The Commission quoted figures showing migrants from within the EU appeared to have boosted the bloc’s aggregate gross domestic product by 0.28 per cent since 2004.