Boris Johnson has been warned he may cause a fracturing of national unity if he fails to listen to regional concerns about the easing of lockdown restrictions.

Greater Manchester Mayor Andy Burnham spoke out as a poll reported public support for the UK Government’s handling of the Covid-19 crisis had slipped.

Mr Burnham said the Prime Minister did not inform civic leaders of his easing of restrictions in advance and said the dropping of the Stay at Home message felt “premature”.

While cases of coronavirus have been easing in the South East, Mr Burnham believes the loosening of restrictions came too quickly for the North.

“On the eve of a new working week, the PM was on TV ‘actively encouraging’ a return to work. Even though that would clearly put more cars on roads and people on trams, no-one in Government thought it important to tell the cities that would have to cope with that,” Mr Burnham wrote in The Observer.

“The surprisingly permissive package might well be right for the South East, given the fall in cases there. But my gut feeling told me it was too soon for the North.

“Certainly, the abrupt dropping of the clear Stay at Home message felt premature.

“If the Government carries on in the same vein, expect to see an even greater fracturing of national unity. Different places will adopt their own messaging and policies.”

Speaking to BBC Breakfast on Sunday, Mr Burnham called for the Government to publish a regional breakdown of the R value – which measures how many people on average one infected person transmits the disease to – to help local authorities decide when to reopen schools following opposition from unions to Government plans to start sending some primary school children back from June 1.

He said: “People do not have the R information at the moment. They can get it, but it’s not formally published by the Government.

“There’s a very different picture in the north, particularly in the north east, where the R is the highest, so I can understand concerns [about lifting lockdown measures].

“Let’s get back around the table, look at the evidence and have some flexibility in terms of how [children] return to school because it will be different for different places.”

Meanwhile, only 39% of Britons approve of the Government’s response – down from 48% a week ago – according to an Opinium survey of 2,005 adults on Wednesday and Thursday.

Those saying they disapproved rose from 36% to 42%.

It comes as the Government announced a £93 million investment to bring forward the opening of a new vaccine-manufacturing centre ready to begin production if a coronavirus vaccine is found.

The not-for-profit facility – located on the Harwell Science and Innovation Campus in Oxford – will open 12 months earlier than planned in summer 2021, and will have the capacity to produce enough doses for the entire UK population in as little as six months, the Department for Business, Energy and Industrial Strategy said.

Mr Johnson, meanwhile, has written in the Mail on Sunday that British people’s “fortitude” will enable them to survive the Covid-19 crisis and regain “the freedoms they hold dear”.

Elsewhere, Education Secretary Gavin Williamson has appealed to teaching unions to work with the Government to find “practical solutions” to enable schools in England to begin re-opening.

His plea came amid fears that plans to start the phased re-opening of primary schools from next month, as part of the easing of the coronavirus lockdown in the country, may be scuppered if the unions refuse to co-operate.

Talks on Friday between union representatives and government scientific advisers, intended to provide assurance about the Government’s proposals to enable children to return safely, ended with union leaders saying it had raised more more questions than answers.