A London Assembly member is calling for mandatory landlord licensing across the capital after a Freedom of Information request revealed a lack of prosecutions of rogue landlords by councils.

Caroline Pidgeon (Liberal Democrat) asked all 32 London boroughs what inspections took place last year under the Housing Health and Safety Rating System, designed to spot issue such as sanitation, poor ventilation or heating systems.

While noting that in some cases issues are resolved informally, a quarter of councils in London failed to prosecute a single landlord for providing unsafe accommodation in 2015/2016, the research found.

Another half of London councils prosecuted fewer than ten landlords.

Meanwhile, Newham Council was responsible for 70% of prosecutions under the Housing Act (2004) in London.

There were 13,074 inspections overall, of which just 411 resulted in prosecutions. There were 1,569 improvement notices and 366 prohibition orders served.

Pidgeon said: “Most landlords are of course responsible people, but sadly an element are not. Firm action must be taken to tackle them. Basic standards must be upheld for the two million people in London who now live in private rented accommodation.

“Against a background of severe budget cuts, councils are clearly struggling to find the resources to tackle these issues.

“My survey demonstrates that where mandatory licensing has been introduced, the resources this provides has resulted in a step-change in enforcement activity.

“With the private rented sector growing rapidly in London, it is time to introduce a proper and robust framework of regulation across the entire city.

“The data clearly demonstrates that only a rigorous regime of licensing will result in the enforcement needed to put an end to the problem of rogue landlords across every part of London.

“I hope London Mayor Sadiq Khan will take this issue seriously.”