Prime Minister Boris Johnson has defended Dominic Cummings, saying: “The advice makes it absolutely clear that if you have particular childcare issues that is a factor that has to be taken into account.” So what did the advice say?
The stay at home guidelines say people who live with someone who develops symptoms "must stay at home and not leave the house for 14 days". https://www.gov.uk/government/publications/covid-19-stay-at-home-guidance/stay-at-home-guidance-for-households-with-possible-coronavirus-covid-19-infection
The same guidelines also say: “If you are living with children: Keep following this advice to the best of your ability, however, we are aware that not all these measures will be possible.”
On 24 March, England's deputy chief medical officer Jenny Harries was asked by a journalist: “Imagine you've got a two-year-old who is healthy and both parents or an only parent gets ill - what is meant to happen to that child?”
Harries said if there was no access to formal care support or to family ”they will be able to work through their local authority hubs”. She did not explain exactly what that would mean.
The government also has a page of guidance on essential travel. It says this "does not include visits to second homes... whether for isolation purposes or holidays. People must remain in their primary residence." https://www.gov.uk/government/news/covid-19-essential-travel-guidance