Rents fell by 0.8% in prime central London residential in July, according to new research from Knight Frank.

The figures bring the annual decline in prime residential rental values in the capital to -1.1% since last October – the biggest drop since monthly records began in April 2011.

However, the research showed that rents in prime central London are still 25% higher than at the trough of the market in 2009.

And there was an upturn in the lettings market in volume terms, with 30% more tenancies being agreed compared to the same month in 2011, the figures showed.

Liam Bailey, Knight Frank’s head of residential research, said: “We have noted how rents have been edging down in prime central London since October last year. The rate of this decline has been fairly sedate, and while July’s 0.8% fall marks the biggest decline since April 2011, rents in prime central London are still 25% higher than in the second quarter of 2009.”

He added: “Despite the headline rental decline for prime central London residential, some areas are seeing rental growth, with rents in the City of London increasing by an average of 0.6% during July – up 2.1% over the past 12 months.”