The UK government has defended Boris Johnson after a photograph emerged of the prime minister taking part in a Christmas quiz last December when London was under COVID-19 restrictions. The Sunday Mirror published a picture of Johnson reportedly playing quiz master while flanked by two colleagues, one of whom is draped in tinsel and the other wearing a Santa hat, in the Number 10 library. The quiz is said to have taken place on Dec. 15, 2020, when London was in tier two restrictions, meaning there could be no mixing of households indoors, apart from support bubbles. Official guidance at the time set out that there should not be work lunches or parties “where that is a primarily social activity” and was not exempted for “work purposes.” Downing Street confirmed that Johnson did “briefly” take part in the “virtual” quiz. A Number 10 spokeswoman said: “Downing Street staff were often …