Shabana Mahmood told “white liberal” hecklers to “fuck right off” after being accused at an on-stage event of copying the policies of Nigel Farage’s Reform UK.

The home secretary was barracked by a man who said he wanted to “personally thank you for out-Reforming Reform” during a live interview in central London on Monday. Two other audience members shouted “refugees welcome” as the man was removed by security.

Speaking to the comedian Matt Forde, Mahmood said she would not be put “in her box” and accused the protesters of trying to “delegitimise” the “perfectly valid” concerns many people have with high levels of immigration.

The clash took place as Mahmood faces pressure from Labour MPs and cabinet colleagues to water down hardline plans for asylum and immigration.

Mahmood told Forde’s Political Party podcast at the Duchess Theatre that claims she was chasing Reform votes were “just a way of delegitimising the point of view that I bring to the table”.

“It’s also a way of delegitimising the perfectly valid, legitimate views of millions of people in this country, including ethnic minorities in this country. And it’s not acceptable, right? And also, you’re trying to put me in a box, which includes a lot of people who think I don’t even belong in my own country.

“That’s why I said this individual can just fuck right off, because I know I belong in my own country. You’re not going to be able to do that to me,” she said.

She said there was an aspect of racism to the claims. “I do think there is that element of it, which is: ‘How dare you, a brown woman, say a thing that we white liberals think you’re not allowed to say?’ Well I’m saying it.”

She also told Forde that she was frustrated at Labour’s lack of progress in government.

“We ourselves in the Labour party are getting in our own way.”

A campaign group that said it coordinated the protest against Mahmood disputed her accusation that they are “white liberals”.

Green New Deal Rising said the man who began the disruption is a 32-year-old called Joe who is a person of colour and of a migrant background.

“As someone who migrated here when I was four and grown up here, I know the value migrants bring to our country,” Joe said in the statement.

Mahmood plans to end permanent protection for refugees, who will instead have their asylum grants reviewed every 30 months and forced to return home once it is safe to do so.

Refugees will not be able to bring their family to the UK until they can afford to live self-sustainably, and refugees will only start to qualify for permanent settlement after 20 years.

Mahmood plans to double the time it takes for most overseas workers to gain permanent settlement in the UK from five to 10 years.

She has recently come under attack for claiming that the overhaul of settlement rules will save £10bn.

The IPPR thinktank pointed out that estimates from the government’s own Migration Advisory Committee show dependents making net positive financial contributions until they stop working, claim the state pension and start having higher health costs.