Britain's nominee for the European Commission will be put in charge of crafting a response to terrorism and promoting intelligence-sharing, Commission President Jean-Claude Juncker said, a tough role amid a spate of attacks in western Europe.

Former British Prime Minister David Cameron nominated Julian King - Britain's ambassador to France - as the country's representative at the European Commission to replace Jonathan Hill, who resigned after Britons voted on June 23 to leave the bloc.

The Commission, the executive branch of the European Union, said King's Security Union portfolio would include setting up a European response to terrorism, organised crime and cybercrime.

In his appointment letter, Juncker said he would like King to improve information and intelligence sharing, "including through initiatives to upgrade Europol's European Counter-Terrorism Centre into a stronger structure and through the development of efficient and interoperable information exchange systems."

London, which has in the past pushed for greater EU cooperation on security matters, welcomed the announcement.

"Security is a vital issue for all Member States and co-operation across the EU can help to better protect us all from the range of threats we face," a spokeswoman for Prime Minister Theresa May said in a statement.

King's appointment must now be endorsed by the European Parliament.

Juncker interviewed King on July 11, and the British diplomat is expected to appear in front of the EU legislature in early autumn.

King has served in Brussels before, notably as chief-of-staff to two previous British commissioners, Peter Mandelson and Catherine Ashton in 2008-09. He has also been ambassador to Ireland, the EU state with possibly the most to lose from Brexit. He took up his post in Paris five months ago.