Sir John Major has launched a blistering assault on Tory leadership candidates who have suggested parliament could be prorogued to push through Brexit, saying they were indulging in “gold-plated hypocrisy” and lacked leadership qualities.

He also ridiculed the suggestion, put forward by many Tory candidates, that it was possible to leave the EU on 31 October, saying they were hoping for a miracle that was not going to happen.

Britain’s fate after Brexit depended on the standing of its next prime minister, including whether they were respected internationally and wanted to have a global perspective, rather than just represent a faction, he said.

Boris Johnson, the leading contender to replace Theresa May, has refused to rule out the idea of proroguing parliament.

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The former prime minister, speaking at Chatham House, said: “When you have people suggesting that you prorogue parliament because parliament may take a different view from a particular faction in the House of Commons you are heading in very dangerous territory.

“When you look back at British history, you cannot image Disraeli, Gladstone, Churchill or Thatcher, even in their most difficult period, saying ‘let us put parliament aside while I carry through this difficult policy’ … it is fundamentally unconstitutional … and to hear that argument come from the people who in the Brexit debate talked about parliamentary sovereignty being at stake, it is not just fundamentally distasteful, it is hypocrisy on a gold-plated standard.”

He added: “I don’t think that can possibly be allowed to stand. I don’t think the House of Commons will allow it to stand.

“I don’t think anybody who proposes that, or even let it flit through their mind for a second, has any understanding of what parliament is about, what sovereignty is about, what leadership is about, or what the UK is about and the sooner the House of Commons stamps on the idea absolutely, comprehensibly and forever, the better.”

Asked if the next prime minister could implement Brexit by 31 October – with many Tory leadership hopefuls, including Johnson, ruling out any attempt to seek an extension – Major said: “Those people who are suggesting that it can be done have their fingers crossed behind their back, whistling gently into the wind and hoping for some miracle where it might be possible.”

He said the false promises would only lead to future further disillusionment.