Prime Minister Jüri Ratas attended a reception for heads of state with the UK's Queen Elizabeth II on Tuesday while on an official visit to London for the 70th-anniversary meeting of NATO.
The two-day NATO meeting will end on Wednesday.
Ratas later attended a reception with Prime Minister Boris Johnson. Ratas was accompanied by his wife Karen and the pair were photographed taking a selfie in front of the door of 10 Downing Street.
Editor: Helen Wright