Early Edition with Kate Hawkesby

British Prime Minister Boris Johnson on Sunday praised the "colossal" effort to airlift civilians from Kabul, as U.K. troops and diplomats flew home after the two-week mission, ending 20 years of British military involvement in Afghanistan.In a video message, Johnson praised the "colossal exertions" of British troops engaged in "a mission unlike anything we've seen in our lifetimes."But his government is facing criticism for leaving behind hundreds, or even thousands, of vulnerable Afghans whom the U.K. had promised to protect.The U.K. ambassador to Afghanistan, Laurie Bristow, was among those who arrived at RAF Brize Norton northwest of London on Sunday, hours after the government announced that all British personnel had left Kabul. More flights bringing back approximately 1,000 U.K. troops from Kabul airport were due throughout the day.Britain says it has evacuated more than 15,000 U.K. citizens and vulnerable Afghans in the past two weeks, but that as many as 1,100 Afghans who were entitled to come to the