Greater Manchester mayor Andy Burnham says Boris Johnson faces a “fracturing of national unity” if he ignores the regions in the coronavirus outbreak.
Mr Burnham said mayors had not been told the lockdown was being eased.
Writing in the Observer, he warned that without additional support for the regions, there was a danger of a “second spike” of the disease.
His intervention came as the Prime Minister accepted that there had been “frustration” over lockdown rules.
The devolved administrations in Scotland, Wales, and Northern Ireland have refused to follow Mr Johnson’s easing plan, while cities such as Liverpool have said they will not start re-opening schools next month as the government wants.
Mr Burnham said that despite having taken part in a call two weeks ago with Mr Johnson and eight other regional mayors, he was given no real notice of the measures announced last Sunday.
“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,” he said.
Mr Burnham said the lack of notice was not the only issue Greater Manchester had to deal with.
“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,” he said.
“Certainly, the abrupt dropping of the clear ‘stay at home’ message felt premature.”
To prevent further divisions, he urged Mr Johnson to appoint West Midlands mayor Andy Street to represent the English regions on the government’s Cobra civil contingencies committee.
“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,” he said.
“Nervousness in the North about the R number will see more councils adopt their own approach on schools, as Liverpool, Gateshead and Hartlepool are doing. Arguments will increase about funding.
“And if we don’t get the help we need, there is a risk of a second spike here which, in turn, will pass the infection back down the country through the Midlands to London.”
The prime minister wrote in the Mail on Sunday that more complicated messages were needed during the next phase of the response and as restrictions changed.
In his article, Mr Johnson said changes to lockdown restrictions in England – such as unlimited exercise outdoors – were possible due to the public’s “good common sense”.
In a reference to confusion and criticism of the government’s new message urging people to “stay alert”, Mr Johnson said the government was attempting something that has “never had to be done before”.