The head of the EU executive has delivered a scathing denunciation of David Cameron’s proposals to curb the rights of Europeans working in Britain, suggesting the British are stigmatising and “beating up” poorer east Europeans working legally in the UK. In his first comments on the prime minister’s initiative, Jean-Claude Juncker, the new president of the European commission, insisted the principle of free movement for labour in the EU meant there could be no discrimination against any EU countries.