Penny Mordaunt has sparked a row in the House of Commons after she accused Labour frontbenchers of sneering at the St George’s Cross flag.

The Commons Leader branded members of the opposition party “plastic patriots” during a heated business questions session on Thursday.

Labour former minister Dawn Butler defended her party, stating that Sir Keir Starmer has “wrapped” himself in the English flag.

Ms Mordaunt told MPs: “While they criticise and sneer at those that do not celebrate St George’s flag, they are allowing some of them to occupy the frontbench.

“Today’s Labour Party are packed with the same old socialists and a few new plastic patriots, and no amount of window dressing can…”

Ms Mordaunt was interrupted by shouts from the Labour benches and Ms Butler raising a point of order.

The Brent Central MP accused Ms Mordaunt of misleading the House, adding: “It’s a matter of fact that this side of the House celebrated St George’s Day, we all put it on our social media.

“The leader of our party has made a point of wrapping himself in the flag. The Leader of the House is completely incorrect in what she just said to the House.”

Ms Mordaunt replied: “I’m happy to add, the truth hurts.”

Meanwhile, Labour’s shadow Commons leader Lucy Powell criticised the Tories for being a “chaotic mess”.

Ms Powell said: “The truth is, no matter how much their mayors and candidates hide behind their green and purple branding, there’s no escaping the fact that they are standing on the woeful record of this Tory Government.

“We have a plan, and they might not like it, but we do: to bring down waiting lists, to deliver lower energy bills, to build more homes, and as we have set out today to reform our railways in the interest of the travelling public. Not more free cash, as some have said.

“The truth is a vote for the Conservatives is a vote for this chaotic mess to continue.”

Later in the session, SNP MP Deidre Brock urged Ms Mordaunt “to overcome this vow of silence” on Brexit, as she accused MPs of shutting their eyes to the harms it has caused.

The SNP spokeswoman said: “This place shuts its eyes to the devastating impact it is having on people’s lives and businesses.

“Now Scots are accustomed to being ignored and over-ruled and treated with disdain by this Government, but being dragged out of the EU has been an economic and a social disaster for us.”

Ms Mordaunt replied: “Despite what (Ms Brock) says, we have now become the fourth largest exporter in the world.”

She added: “No surprise they don’t want to deal with the reality of the situation, given the reality of the situation now with the SNP – a minority administration, their failings, and some very serious issues that we all know are now subject to prosecution as well as investigation, means that not even the Greens want anything to do with them.”

Elsewhere in the session, Labour MP Sir Chris Bryant argued there should be risk assessments following an MP’s arrest or charge with a sexual offence, to “burnish” the reputation of the Commons.

The Rhondda MP said: “It’s standard practice in schools, universities, the NHS, local government and in government departments, if somebody is arrested for or charged with a sexual, violent crime, that there will be a risk assessment made following, potentially, if necessary, by an exclusion or suspension from work pending further investigations and if necessary a trial.

“The standards committee of the House and House of Commons Commission agrees that we should have something similar for this House and that’s been sitting on the stocks now for several months.

“I understand of course that there are perfectly legitimate questions about exactly how that should operate, but what I don’t understand is why (the Leader of the House Penny Mordaunt) has not tabled the motion that came straight from the House of Commons Commission which I would think was her duty as Leader of the House.”

He added: “We really do need to burnish the reputation of this House, not tarnish it. Can she please give us a date as soon as possible? So we can come to a legitimate debate and view on how we can progress this.”

Ms Mordaunt replied: “I hope to be able to do that at the next business statement that I give.”

She added: “I take these matters seriously and I’d be very happy to bring forward that debate.”