Boris Johnson has been under pressure to explain why he broke coronavirus lockdown rules to exercise at a park seven miles away from Downing Street.
Johnson was spotted wearing a hat and face mask at Queen Elizabeth Park on Sunday.
A source told the Evening Standard that Johnson was exercising and had been accompanied by his security detail.
But official government guidance says exercise should be limited to once a day and within your local area.
The same source said Johnson was struck by the number of people out and about.
“He did note how busy the park was and he commented on it at the meeting last night, ” the source said.
“He was concerned about if people were following the rules and was concerned after his cycle ride around the park.”
The prime minister’s spokesman was unable to give any information today on why Johnson had gone to Stratford and why it was within the rules.
This comes as Johnson today said he is ready to tighten lockdown restrictions further as he expressed alarm at the number of people becoming “complacent” ever since a vaccine began being rolled out.
He warned that Britain was in the midst of “a very perilous moment”.
“This is the moment when that degree of false confidence, false complacency, and that when you look at what has happened in the NHS that complacency is not merited.
“More important than us just pushing out new rules, people have got to follow the guidance.
“In supermarkets, people need to be keeping their distances, making sure that they’re wearing masks, doing the right thing.”