President George Vella is in London for meetings with Queen Elizabeth at Buckingham Palace and the Prince of Wales at Clarence House.
He will also deliver a lecture at Chatham House on current security challenges in the Mediterranean.
The president, accompanied by Mrs Vella, will also visit patients and their relatives at the Puttinu Cares apartments and homes run by the Franciscan and Augustinian sisters.
Dolores Cristina is acting president.