Nigeria’s president, Muhammadu Buhari left for London yesterday for fresh treatment of an undisclosed illness.

His last official act before leaving for London was to meet the 82 schoolgirls kidnapped in Chibok in 2014 after they were released by Boko Haram Islamist militants.

His health has been a major cause of concern in a country where there are fears that a power vacuum could affect its recovery from recession.

In a brief message, the president said "there is no cause for worry".

Mr Buhari, 74, has left Vice-President Yemi Osinbajo in charge, just as he did when he left for London in January for seven weeks of medical leave.

Mr Osinbajo was widely praised at the time for his performance as acting president.

Details have not been provided as to when the ailing president is expected to return to his country but Nigerians have expressed concerns of the deteriorating health of their first gentleman of the federal state.

Earlier this year, Buhari spent more than a month in London for medical attention.

Buhari's unhealthy start to 2017

19 January - Leaves for UK on "medical vacation"

5 February - Asks parliament to extend medical leave

10 March - Returns home but does not resume work immediately

26 April - Misses second cabinet meeting and is "working from home"

28 April - Misses Friday prayers

3 May - Misses third cabinet meeting

5 May - Appears at Friday prayers in Abuja

7 May - Travels to UK for further treatment