Category 1: Travellers should self-isolate, even if asymptomatic, and call NHS 111 to inform of recent travel. Go home or to your destination and then self isolate. (for further info click on the gov.uk link)
Category 2: Travellers do not need to undertake any special measures, but if they develop symptoms they should self-isolate and call NHS 111.
The guidance for Italy, Iran, Daegu or Cheongdo (Republic of Korea), Laos, Myanmar, Cambodia and Vietnam applies to individuals who returned from these specific areas on or after 19 February 2020. (for further info click on the gov.uk link)