My initial reaction at the time was that this was some kind of try-on, Boris Johnson said of the moment when I first approached Downing Street with the news we were about to publish a story about lockdown parties at the heart of government.At the time, it seemed implausible to me that there could have been an illegal event at No 10 almost a year earlier that I had not heard about before, the former prime minister said in his written evidence to the privileges committee on Tuesday.