The Commons speaker said he had not had any warning of the move and claimed it was “blindingly obvious” that it was designed to stop MPs debating Brexit.
Mr Bercow suggested Mr Johnson’s decision would “undermine his democratic credentials”.
His attack on the prime minister – unusually strong for a sitting speaker – came amid widespread outrage at the decision to prorogue parliament from early September.
Mr Johnson claimed that the break was normal ahead of a Queen’s Speech and insisted it was “completely untrue” to suggest that the highly controversial move was an attempt to stop MPs blocking a no-deal Brexit.
But Mr Bercow said: “However it is dressed up, it is blindingly obvious that the purpose of the prorogation now would be to stop parliament debating Brexit and performing its duty in shaping a course for the country.”
“At this time, one of the most challenging periods in our nation’s history, it is vital that our elected parliament has its say. After all, we live in a parliamentary democracy.
“Shutting down parliament would be an offence against the democratic process and the rights of parliamentarians as the people’s elected representatives. Surely at this early stage in his premiership, the prime minister should be seeking to establish rather than undermine his democratic credentials and indeed his commitment to parliamentary democracy.”
The decision to suspend parliament in the second week of September – a month before the Queen’s Speech on 14 October – wil cut the time available for MPs to pass legislation to prevent no deal.
It means parliament will be sitting for a total of just over three weeks before the 31 October Brexit deadline.
Mr Johnson also faced an outpouring of anger over the decision from other MPs.
Labour leader Jeremy Corbyn called the move “a threat to our democracy”. He said: “I am appalled at the recklessness of Johnson’s government, which talks about sovereignty and yet is seeking to suspend parliament to avoid scrutiny of its plans for a reckless no-deal Brexit. This is an outrage and a threat to our democracy.
“That is why Labour has been working across parliament to hold this reckless government to account, and prevent a disastrous no deal which parliament has already ruled out.
“If Johnson has confidence in his plans he should put them to the people in a general election or public vote.”
Conservative rebel Dominic Grieve, the formal attorney general, said proroguing parliament was “unprecedented” and claimed Mr Johnson would “come to regret it”. He suggested MPs could vote down the government before parliament is suspended.
He said: “I think that the prime minister’s decision is deeply questionable and frankly pretty outrageous.
“He knows very well that we’re in the middle of a national crisis, he knows very well that parliament is extremely concerned about the possibility of a no-deal Brexit and this has very little to do with starting a new session of parliament – it’s a deliberate attempt to make sure that parliament doesn’t sit for a five-week period.”
Mr Grieve suggested that MPs could vote down the government if no other way can be found to avoid parliament being prorogued. He said Mr Johnson’s opponents would move “very quickly to a vote of no confidence in the government”, adding: “If it is impossible to prevent prorogation then it is going to be very difficult for people like myself to have keep confidence in the government and I can well see why the leader of the opposition might wish to call a vote of no confidence.”
Justine Greening, another former Tory cabinet minister, said it was “totally wrong to prorogue parliament” and added: “Everyone can see this for what it is, a grubby attempt to force no deal.”
Liberal Democrat leader Jo Swinson said: “Shutting down parliament would be an act of cowardice from Boris Johnson. He knows the people would not choose a no deal and that elected representatives wouldn’t allow it. He is trying to stifle their voices.”
She added: “This is an attempt to govern without parliament. It’s pretty unprecedented and the government will come to regret it.”
Yvette Cooper, chair of the Commons Home Affairs Committee tweeted: “Boris Johnson is trying to use the Queen to concentrate power in his own hands – this is a deeply dangerous and irresponsible way to govern.”
However, the move to suspend parliament was welcomed by Brexiteers, including Mr Johnson’s Commons partners in the DUP.
The party’s leader, Arlene Foster, said: “This has been the longest parliamentary session since the union of England and Scotland in 1707.
“We welcome the decision to hold a Queen’s Speech marking the start of a new session of parliament on 14 October where the government will set out its new domestic legislative agenda. This will be an opportunity to ensure our priorities align with those of the government.”
And Nigel Farage, leader of the Brexit Party, said: “The government’s announcement today makes a confidence motion now certain, a general election more likely and is seen as a positive move by Brexiteers. The unanswered question is whether Boris Johnson intends to pursue the withdrawal agreement.”
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