The heir to the throne and the Prime Minister are both in Kigali for a Commonwealth summit and spoke privately for 15 minutes after Charles addressed delegates about slavery.
In a press conference at the Commonwealth summit, Boris Johnson said he would listen and learn following the disastrous losses in Tiverton and Wakefield.
Ministers conceded it had been tough for the ruling party, particularly in the south of England where it lost ground to Labour in London and the Liberal Democrats in its blue wall heartlands.