The House of Commons Speaker, John Bercow, has sought to defuse a row with the government by admitting he muttered the word “stupid” during a disagreement with the leader of the house, Andrea Leadsom, but denied insulting her personally.

In the chamber last Wednesday Bercow was accused of having said in an aside that Leadsom was a “stupid woman”, and swearing before describing her as “useless”, prompting Downing Street to say such language would be unacceptable.

But in a statement to MPs on Monday Bercow said that while he had been annoyed by the government’s decision to schedule a statement on the East Coast rail franchise on an opposition day, he had not insulted Leadsom.

“I thought then, as I think now, that this was very badly handled,” Bercow told MPs. “It was in particular disrespectful both to the house and to the 23 backbenchers who were hoping to participate in the opposition day debate on the Grenfell Tower disaster.

“It was in that context, and that context alone, that, having expressed my displeasure about the matter quite forcefully from the chair, I used the word ‘stupid’ in a muttered aside. That adjective simply summed up how I felt about the way that that day’s business had been conducted.”

This was not directed at Leadsom, Bercow said, telling MPs that anyone who knew her “will have not the slightest doubt about her political ability and her personal character”.

He concluded: “I love this house. I respect all of my colleagues. I hold you all in the highest esteem. It is our duty to get on with the business of parliament, scrutinising legislation, debating issues and standing up for the people we are here to represent.

“For my part I shall continue to speak out firmly for the interests of the whole house and, if from time to time it involves publicly disagreeing with the government’s management of business, then so be it.”

Speaking in the debate after the statement, Leadsom said she took her responsibilities very seriously and she expected all MPs to treat colleagues with “courtesy and respect”.

The claims about Bercow last week came amid wider pressure and scrutiny on the Speaker, who has faced calls to resign over allegations he bullied staff who worked for him. He has denied the claims.

Speaking in a debate after Bercow made his comments, Leadsom said: “I take my responsibilities to this house very seriously. As you said last week, Mr Speaker, we have a responsibility to safeguard the rights of this house.

“As leader of the house, I seek to do exactly that, treating all members of parliament with courtesy and respect. I hope and expect all honourable and right honourable members to do likewise.”

Leadsom did not complain to the parliamentary standards commissioner about the alleged comments.

It is understood she did not to want to complain herself because she did not want to jeopardise her independent complaints and grievance policy. The final proposals, which are due out before the summer recess in July, have to be signed off by the House of Commons commission, which is chaired by Bercow.