Working closely with ambassador Anthony Brenton, Barbour will become press secretary in the summer, leading a team of eight.

He leaves his current role on 19 January and will start a six-month training programme with the Foreign and Commonwealth Office on 22 January, focused on learning Russian.

He previously worked for the FCO as a press ­officer. He took unpaid leave to join H&K’s PA team in January 2004 in search of private sector experience.

At H&K, Barbour reports to Tim Fallon, head of the corporate affairs (UK) practice and MD of PA (UK).

The WPP-owned agency is looking at various options to replace Barbour but was keen to stress ‘the team will remain as strong’.

In Moscow he will replace Anjoum Noorani, who was promoted to the post in  March 2006. Noorani hopes to return to the FCO in London after a handover period with Barbour.

Barbour’s new remit has two aspects: media engagement and public diplomacy. The first involves working with local media to promote Britain. The second aims to increase understanding of Britain and British policies among the Russian public. Working with the British Council, this will involve organising cultural events, such as an annual film festival.

A spokesman for the British Embassy in Moscow told PRWeek: ‘This is one of the most challenging but rewarding press jobs in all the British embassies.’

He added: ‘Moscow has a diverse and developed media scene and there are many deep-rooted misconceptions of Britain.

‘The British Embassy is trying to build a relationship with understanding and trust in a country that really matters.’