UK Prime Minister David Cameron will promise on Tuesday to fight for Turkey to join the European Union and he holds that opponents of Turkish membership are protectionists or prejudiced.

Turkey has begun the slow process of accession talks with the 27-member EU, but there is no consensus as whether it should be given full membership. France has taken the strongest stand against Turkish entry.

On his first visit to the country since becoming prime minister in May, Cameron will say Turkey would bring greater prosperity and political stability to the bloc thanks to its vast economic potential and growing influence in the volatile Middle East and central Asia.

Cameron will say in his speech that those who oppose Turkish accession fall into three categories: those who see Turkey's growing economic power as a threat, those who think the country should choose between East and West, and the prejudiced who misunderstand Islam.

He will argue that it is precisely because it is a secular state with a Muslim majority that Turkey should be welcome in the EU, which, he considers, is defined by values, not religion.