President Muhammadu Buhari, on Sunday night met with Vice President Yemi Osinbajo, Senate President Bukola Saraki, Speaker Yakubu Dogara and Zamfara State Governor, Abubakar Yari ahead of his trip to London.
Shortly before the meeting, he expressed delight on the freedom of 82 Chibok girls released by Boko Haram on Saturday.
In a statement released by his Special Adviser on Media and Publicity, Femi Adesina, the duration of Buhari's stay in London will be determined by his doctors.
Adesina, however, said the President had transmitted a letter to the National Assembly as required by the law.
"President Muhammadu Buhari proceeds to London tonight for follow-up medical consultation with his doctors.
"He had planned to leave Sunday afternoon, but decided to tarry a bit, due to the arrival of 82 Chibok girls who arrived Abuja earlier in the day.
"The President wishes to assure all Nigerians that there is no cause for worry. He is very grateful for the prayers and good wishes of the people, and hopes they would continue to pray for the peace and unity of the nation.
"The length of the President's stay in London will be determined by the doctors. Government will continue to function normally under the able leadership of the Vice President.
"President Buhari has transmitted letters about the trip to the Senate and the House of Representatives, in compliance with Section 145 (1 ) of the 1999 Constitution", the statement reads.