LONDON, July 18 (Reuters) - Prime Minister Boris Johnson urged the British public to be cautious and said they must self-isolate when told to do so as COVID-19 restrictions are lifted in England on Monday. "Please, please, please, be cautious," Johnson said in a video from his own period of self-isolation, which was announced earlier on Sunday. read more "Go forward tomorrow into the next step with all the right prudence and respect for other people, for the risks that the disease continues to present and, above all, please please please when you"re asked to get that second jab ... please come forward and do it."