“Beleaguered” Prime Minister Boris Johnson should not be given sole power over when a general election is called, peers have heard.

The warning came as the House of Lords inflicted a defeat on Government plans to change how general elections are called.

Conservative former minister Lord Cormack claimed that the Prime Minister would be able to “threaten his parliamentary troops” with an early election because of his “personal difficulties” if the Dissolution and Calling of Parliament Bill were allowed to pass unchanged.

The Bill would repeal the Fixed-term Parliaments Act 2011 (FTPA), which was introduced by the coalition government to help provide stability by ensuring general elections occurred every five years.

The existing Act allows the Commons to trigger elections, but the proposed legislation would return this power to the Prime Minister.

The new provisions also confirm a parliament’s maximum term is five years.

The Government has argued the FTPA had led to stalemate during the previous turbulent parliamentary session when Theresa May was in office.

But peers voted by a majority of 40 (200 in favour, 160 against) for an amendment allowing MPs to hold a vote on whether Parliament is dissolved, with a simple majority required for a general election to go ahead.

Speaking in support of the amendment, Lord Cormack said: “I do not think it is right that a Prime Minister, particularly a beleaguered Prime Minister, should be able to threaten his parliamentary troops to plunge the country into uncertainty merely because he is in personal difficulties.

“Not one of us knows what is going to happen in the coming days, weeks, and months… but what is important is there should be a seemly transition which does not involve compromising the integrity of the Sovereign, particularly in this year of all years, and that there should be a clear opportunity for the House of Commons to decide whether they wished to plunge the country into a general election or not.

“All this amendment does is to give that chance to the House of Commons.”

But Lord Bridges of Headley said he wanted to “return to a system in which a Prime Minister can call an election and that election happens. No ifs, no buts, no parliamentary votes, no court cases”.

The Conservative former minister added: “It is indeed one person’s decision to call an election, but that decision should automatically give power to millions of people who can pick up that stubby pencil and decide on the future of the country.

“Power rests with them and if they want to punish the Government for calling an election early, as we saw to our costs, they can do so.”

Labour frontbencher Baroness Smith of Basildon disagreed, saying: “The fundamental basis of our democracy is that power flows from the ballot box to the elected chamber of Parliament, the House of Commons, and the Government derives its authority from the House of Commons and it is responsible to the House of Commons.”

Cabinet Office minister Lord True described the FTPA as “a failed 21st century experiment”, asking peers to reject the amendment.

He added: “It risks recreating the conditions of the very paralysis we all lived so recently and which we all told ourselves that we would never want to see again.

“My lords, we should not risk returning to that, we should reflect on the wisdom of ages, we should take pride in our constitutional practice over generations before 2011, and reject this amendment.”

Despite Lord True’s appeal, peers backed the amendment, put forward by former lord chief justice, Lord Judge.

The Lords’ amendments to the Bill will be considered by the House of Commons later this year.