From February 2017 to February 2018, the average price of a residential property in the capital dropped by 1.0% - equivalent to around £5,000.
Tower Hamlets (which includes trendy neighbourhoods like Hackney Wick and Bethnal Green) saw the biggest year-on-year fall: a hefty 7.9%.
Hammersmith and Fulham (-5%) and the City of London (-4.4%) also saw significant slips, but outer London boroughs Redbridge (+8.9%), Havering (+4.2%), Bexley (+4.1%) and Bromley (+3.8%) all posted notable increases.
Overall, according to the ONS report, the average house price in the UK has risen 4.4% year-on-year. The areas that experienced the highest price hikes from 2017-18 are the West Midlands (7.3%), East Midlands (6.3%), Scotland (6.2%), South-west (4.9%), North-west (4.8%) and Wales (4.8%).
Despite the London price drop, the average house price in the capital - an eye-watering £472,000 - remains more than double the national average of £225,000.
Commenting on the latest UK property price stats, Thomas White of leading economists PwC said: "Regionally, the picture remains mixed, with London diverging from the rest of the country. Compared to this point last year, prices in London have decreased by 1%, the first time a year-on-year decline in average London prices has occurred since September 2009.
"We broadly expect current market conditions to continue, projecting UK wide house price inflation to be around 4% in 2018.”
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