Boris Johnson has urged people to resist the “temptation” to break coronavirus lockdown rules should the weather hot up this weekend.

The Prime Minister said he understood “everybody may be getting a bit stir crazy”, particularly if they have children in the house, and people may want to “hang out” over the weekend.

However, Mr Johnson, who is continuing to self-isolate after testing positive for Covid-19 last week, warned Britons to “stick with the guidance” in a bid to help ease the pressure on the NHS.

Downing Street said that ministers were prepared to bring in further measures if people ignored the official advice.

“We have said that if the scientific advice is that we need to go further we won’t hesitate to do so,” the Prime Minister’s official spokesman said.

The Met Office believes there will be sunny spells on Saturday after a chilly start while long sunny spells are expected on Sunday, with temperatures forecast to reach 21C (69.8F) in London and the South East, and 20C (68F) in other parts of the country.

Government advice is that people should only leave the house for “very limited purposes”, including shopping for “basic necessities” as infrequently as possible, and one form of exercise a day, either alone or with members of your household.

Any medical need and travelling for work purposes, but only if you cannot work from home, are also included in the criteria.

Mr Johnson, in a video released on social media, said: “I just want to say one crucial thing, one quick thing to everybody thinking about this weekend and what may be some fine weather.

“I reckon a lot of people will be starting to think that this is all going on for quite a long time and would rather be getting out there, particularly if you’ve got kids in the household, everybody may be getting a bit stir crazy, and there may be just a temptation to get out there, hang out and start to break the regulations.

“I just urge you not to do that. Please, please stick with the guidance now.

“This country has made a huge effort, a huge sacrifice, done absolutely brilliantly well in delaying the spread of the virus.

“Let’s stick with it now – remember that incredible clapping again last night for our fantastic NHS. We’re doing it to protect them and to save lives.”

Councillor James Jamieson, chairman of the Local Government Association, said: “With warm weather forecast for the weekend, I like many others will be looking forward to some fresh air.

“I understand families might be tempted to go out and enjoy the sunshine, whether that’s a trip to the coast or seaside, or a picnic in a beauty spot or country park.

“But the Government’s guidance is clear – you shouldn’t go out unless it is necessary and for essential travel or once daily exercise.”