He added: “It breaks my heart to have to insist on these restrictions”.
While there Mr Johnson did not confirm exactly how long the new restrictions could last, they are expected to remain in place for months not weeks.
The Cambridges spent lockdown at Anmer Hall in Norfolk but are understood to be back in London so Prince George and Princess Charlotte could go back to school this week.
Kate is extremely close to her parents Carole, 65, and Michael, 71, and the doting grandparents have often helped out with childcare.
