The rate of Prime London rental growth increased in September while activity was mixed, according to property data consultancy LonRes.  

Agreed lets fell while there was a slight rise in new instructions.

Average rental values increased by 4.6% on an annual basis in September, the fastest rate of growth in 18 months.  Average rental values were 43.5% above their 2017-2019 (pre-pandemic) average. 

LonRes data for September indicated an annual decrease of 14.9% in lets agreed and a 3.4% increase in new instructions.  

The stock of available rental properties increased on an annual basis, with 6.9% more homes on the market at the end of September than a year earlier, although stock levels remain well short of typical historical levels.  

The impact of the Renters Rights Act (RRA) continues to be a key factor, the consultancy claims. 

For tenancies where the annual rent is over £100,000 the Act does not apply, meaning there are effectively two rental markets in the prime niche.  

The proportion of exempt properties varies significantly by area and has been rising with recent rental growth.  In Mayfair & St James’s 36% of properties let so far in 2026 have been over the £100,000 threshold, with Knightsbridge & Belgravia and South Kensington also over 20%. 

Commenting on the findings, Nick Gregori, head of research at LonRes, comments: “The Renters Rights Act is likely to be having an impact here, from both sides of the supply-demand equation.  

“First, some landlords have exited the market, meaning more competition for the remaining properties.  Second, those who have remained may be seeking a premium to account for the perceived greater tenants’ rights.  

“The market continues to adjust to the new regime, complicated further by the high and growing proportion of exempt high value rental properties in some central London neighbourhoods.”