Prices in London are a whopping 13.8% higher than they were a year ago, compared to 3.8% higher in the rest of the country.
In London's outer boroughs prices the average price of £461,937 is more than twice the average in the rest of England and Wales.
Prime inner London property has reached stratospheric levels - an average of £937,110.
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Paramedics were on standby outside the police cordon as armed officers stood by the property.
A team of researchers has taken samples from the ten busiest London Underground lines to work out which are the dirtiest.
The action comes on top of an emergency timetable which has seen hundreds of trains a day being axed.