The London Renters’ Union (LRU) has called on Labour MP Jas Athwal to stand down after a BBC investigation found black mould and ant infestations in his rental properties.

The union, which has 7,000 members across the capital, has also written to Redbridge Council urging it to investigate its former leader over what it called “housing law violations”, after BBC News found Athwal’s flats had dirty communal areas, faulty lights, loose fire alarms.

Athwal also admitted his flats lacked the required licences under a scheme he introduced as Redbridge Council leader, despite earlier claiming compliance.

The MP for Ilford South owns 15 properties, making him the biggest landlord in the House of Commons.

Athwal said he was he was “shocked and sickened” by the state of the flats following the BBC report on the weekend and sacked the letting agency that managed the properties.

When asked about the case this week, prime minister Sir Keir Starmer, said: “It’s not good enough. It’s unacceptable for any landlord, and I’ll be really clear about that. It doesn’t matter whether it’s a Labour MP or anybody else, it’s unacceptable.”

Hester Sullivan, a spokesperson for the LRU, said: “Athwal left his tenants facing toxic mould and dangerous disrepair and has broken laws on licensing, which is a key part of the tenant safety system.

“Athwal has also admitted to refusing to let out properties to renters who receive housing benefit, a practice that prevents many low-income people from accessing adequate housing.”

She added that renters would not have trust in Parliament’s ability to resolve the national housing crisis were Mr Athwal to remain an MP.

In response to the allegation about not accepting tenants receiving benefits, Athwal told BBC London he currently rents to people who are in receipt of housing benefit.

“In my previous comments I was referring to tenants being placed directly by Redbridge Council specifically; it’s this conflict of interest I was preventing while renting properties while serving as the leader of the council,” he said.

Redbridge Council’s Conservative leader Paul Canal has called on Athwal to step down as a councillor – a role he has kept since becoming an MP – and urged the council’s officers to investigate.

A spokesperson said the council was committed to a “fair and consistent process for every landlord applying to the selective licensing scheme”, adding that it would “continue to work with landlords to ensure that they are compliant and their properties are in a condition suitable for tenants.”

Landlord MP sacks letting agent over state of flats but Labour urged to ‘punish him’