Britons will be allowed unlimited exercise from Wednesday as the Prime Minister gave the "first sketch of a road map for reopening society".

Boris Johnson updated the nation tonight on the government's plans on fighting the coronavirus pandemic - and he stressed that lockdown is not over.

Mr Johnson said it would be "madness" to allow a "second spike" of coronavirus, as he reinforced the new "stay alert" slogan.

He added: "We must continue to control the virus and save lives."

Mr Johnson acknowledged that lockdown measures against the spread of Covid-19 have come at a "colossal cost to our way of life".

He said that social distancing must continue, like staying at least two metres apart from people outside of their household, and he did not give the all-clear for people to mix with friends or family outside of their household.

He warned those who break social distancing rules face bigger fines.

The Prime Minister told the televised briefing that, from Wednesday, people in Englannd can take "more and even unlimited amounts of outdoor exercise".

"You can sit in the sun in your local park, you can drive to other destinations, you can even play sports, but only with members of your own household," he said.

"You must obey the rules on social distancing and to enforce those rules we will increase the fines for the small minority who break them."

Shops and primary schools for speific years only could open in June, while Mr Johnson said that parts of the hospitality industry, like pubs and restaurants, could reopen by July at the earliest, subject to conditions, scientific advice and "only if the numbers support it."

Mr Johnson said that from this week anyone who cannot work from home "should be actively encouraged to go to work" but avoid using public transport if possible.

He added that the Government has been working to establish new guidance for employers to make workplaces "Covid-secure".

Mr Johnson said: "And I must stress again that all of this is conditional, it all depends on a series of big ifs.

"It depends on all of us - the entire country - to follow the advice, to observe social distancing, and to keep that R down." (rate of infection below 1).

Reinforcing a new message of 'Stay Alert' rather than 'Stay Home', the Prime Minister said there would be five alert levels, with Level Five being "the most critical" and Level One meaning that Covid-19 was "no longer present" in the UK.

He added that throughout the lockdown period the country had been at Level Four but that steps could now be taken to move to Level Three.

Mr Johnson said:"The Covid Alert Level will tell us how tough we have to be in our social distancing measures - the lower the level the fewer the measures.

"The higher the level, the tougher and stricter we will have to be."

At the beginning of his speech, the Prime Minister said the coronavirus death toll has been "tragic, and the suffering immense".

But he added that obeying the lockdown measures for almost two months had helped prevent a worst case scenario of half a million fatalities.

He thanked everyone for the efforts and sacrifices they have made to limit the spread of the disease, which has been linked to more than 30,00 deaths in the UK.

As a stark reminder that things can swing easily, Mr Johnson said the government and their scientists will be monitoring progress locally, regionally, and nationally and if there are outbreaks, if there are problems, "we will not hesitate to put on the brakes."

Mr Johnson says he will release more details about the government's plan in Parliament tomorrow before answering questions from the public in the evening.