Downing Street refuses to say which cabinet minister will be in charge while prime minister is away

Theresa May is planning to take three weeks of holiday in northern Italy and Switzerland this summer, without naming a cabinet minister to be in charge during her lengthy absence from No 10.

The prime minister will travel to Italy on Monday for about five days, before returning for the weekend and then attending the centenary commemorations of the first world war battle of Passchendaele in Brussels.

She will then resume her holiday by taking a walking break in the Swiss Alps for another fortnight.

The prime minister is expected to travel to and from Italy and Switzerland on commercial flights.

Downing Street refused to say who would be the senior cabinet minister in charge in the UK, saying there would be a rota of figures on call but stressing that May would remain the boss even while out of the country.

It is May’s first break of three consecutive weeks since she became prime minister. David Cameron tended to go abroad for a fortnight and then take a separate week in Cornwall, but Gordon Brown took a month’s break from London to be in his Kirkcaldy constituency in summer 2009.

Tony Blair more regularly took three-week breaks to destinations such as the Caribbean and Italy in the summer.

May appears to holiday annually in Switzerland, where she enjoys walking with her husband, Philip. She was on a walking break in Wales over the Easter recess when she made the decision to go for the snap election that ended with the loss of her majority.