A Labour MP has said he is "shocked" and "profoundly sorry" after it was revealed flats he rents out had black mould and ant infestations.
Jas Athwal, who became the MP for Ilford South in July, said his tenants had been "let down", and pledged that repairs and maintenance work would be completed "swiftly".
He also said he had not previously been aware of the problems by highlighted in a BBC report due to the properties being managed by an agency.
Paul Canal, Conservative leader for Redbridge Council, in north-east London, called for Mr Athwal to resign as a councillor "immediately", describing the conditions of properties owned by Mr Athwal as a "disgrace".
"His role as a councillor is untenable," Mr Canal said.
He said he had called for Redbridge Council to investigate whether Mr Athwal had breached its code of conduct, echoing a similar call made by Andrew Boff, a Conservative member of the London Assembly.
Mr Athwal owns 15 properties, making him the biggest landlord in the House of Commons. The BBC found flats owned by him contained dirty communal areas, lights that did not work and fire alarms hanging loose from the ceiling.
One resident said they had been threatened with eviction by the property's letting agent when they complained.
Mr Canal said he would be reporting the management agency to the police for "threatening behaviour".
Mr Athwal said: "I know it's my responsibility to have issues addressed as soon as they arise and have met the property management company to understand failures in communication.
"I'm profoundly sorry that tenants have been let down and will be reviewing the property management and how matters are escalated going forward."
The Labour MP also admitted that his flats did not have the correct property licences under a scheme he introduced as the leader of Redbridge Council.
In a lengthy statement, he said it had been his understanding that his property licences were up to date, but had "recently seen an email which shared that licences are due to expire" and was "in the process of renewing all licences".
Rented flats owned by Mr Athwal were found to be in poor condition
But Mr Canal said Mr Athwal's licencing issues were "simply scandalous hypocrisy".
He called on Prime Minister Sir Keir Starmer to withdraw the whip while Mr Athwal was investigated.
Labour's 2024 general election manifesto included a commitment to "prevent private renters being exploited and discriminated against".
Richard Blakeway, the housing ombudsman, said there was "a serious gap that needs to be closed" wherein social housing tenants could take complaints to an ombudsman, but private tenants could not.
Speaking to BBC Radio 4's Today programme, he said it was "welcome" that the government had indicated it would compel landlords to become members of a redress scheme.
He added that the current standard for a decent home was "a very low bar" and "outdated".
"So there needs to be a fundamental rethink of what is a decent home in the 21st century."
Mr Athwal has described himself as a "renters' champion", saying he prided himself on being a good landlord who had never evicted a tenant.
Redbridge Council said it was aware of the situation with Mr Athwal's properties, and that while it would not comment on individual cases, it treated all landlords who needed a licence "equally".