The total fines recorded on the Mayor of London's Rogue Landlord Database have reached £24.1 million, research reveals.
Licensing offences alone account for £14.85 million of this figure, representing more than half of all penalties issued across the private rented sector.
And two councils have been accused of 'running a prosecutorial pipeline' that delivers automatic rent repayment orders in most cases.
The data from Kamma highlights the growing financial risks facing the capital's landlords with enforcement measures and new legislation altering the compliance landscape.
Landlord compliance is changing
The firm's chief executive, Orla Shields, said: "The £25 million figure is striking, but the real story is how councils are enforcing.
"Camden and Islington are running a prosecutorial pipeline that turns council convictions into near-automatic rent repayment orders for tenants.
"Tower Hamlets is providing free legal representation."
She added: "With 162 schemes now active and the Renters' Rights Act in force, the compliance environment has fundamentally changed.
"For agents in particular, the assumption that licensing complexity is someone else's problem is one the fine data clearly no longer supports."
Number of schemes rockets
The volume of active landlord licensing schemes has expanded rapidly, with 162 now in operation across London.
A third of these were introduced within the last 12 months, meaning that 88% of the city is now covered by some form of property licensing.
Discretionary licensing restrictions are currently in force in 28 of the 32 London boroughs.
Letting agents are increasingly being targeted alongside property owners too.
Landlord fines are rising
Kamma, a platform for agents to help handle licensing, also found that the average fine for an agent has risen 14.46% since November 2025 to £7,300 per offence.
This trend was evidenced in January when Haringey Council issued a combined fine of £12,500 to a landlord and their agent for an unlicensed property in Tottenham.
The Renters' Rights Act, which took effect on 1 May, has further increased the costs of non-compliance.
Maximum civil penalties have risen from £30,000 to £40,000 per offence, while the maximum rent repayment order (RRO) has doubled.
Also, tenants are now permitted to claim back up to 24 months of rent for breaches of the regulations.
Landlord enforcement varies
It doesn't help landlords that enforcement strategies vary by borough, with Waltham Forest recording the highest total value of fines at £5.9 million from 714 cases.
Camden has pursued the highest volume of prosecutions, recording 964 cases.
In contrast, Kensington & Chelsea has focused on high-value prosecutions, with the average fine exceeding £108,000 per case.
Some local authorities are also providing direct assistance to tenants to pursue financial claims.
For example, Tower Hamlets has secured more than £1.3 million for renters by providing legal support for RROs at the First-tier Tribunal.
Meanwhile, councils in Camden and Islington are running prosecution and tenant support services in parallel.
Landlords face financial threats
The managing director of Accommodation for Students, Simon Thompson, said: "Landlords in London appear to be facing escalating financial threats due to rigorous council enforcement strategies.
"Failing to have the correct documentation now triggers substantial penalties alongside expensive tenant repayment claims."
He added: "The big fines for non-compliance in the Renters' Rights Act for landlords don't help and makes ignorance a costly mistake for every investor.
"Constant vigilance regarding local council regulations is essential to protect rental income from what has been called prosecutorial pipelines."
