The London market looks to be unravelling dramatically – and not just in its prime central postcodes – as it appears that buyers are staying away while sellers belatedly attempt to cash in.

Sales across the whole of London are sharply down, while supply is up – by 32% according, yesterday,  to the property website Home. It described the surge in new instructions as “startling”.

It is in central London that agents are reporting the steepest falls in sales as buyers stay away.

Richard Barber, partner at Knightsbridge-based W.A. Ellis, said that according to Lonres which tracks all property deals across central London, in June, transactions of houses were down 45% compared with June last year, and all transactions (ie, of flats as well as houses) down by 25%.

He said: “In June, only 185 properties were sold, compared with 249 properties in June 2013. It is the underlying reduction in the volume of transactions which is of most concern.”

He said that last month, only 27 houses were sold by central London agents, compared with 49 last year.

He said: “The underlying factors are very apparent to close observers of the market: the combination of mansion tax threats, higher Stamp Duty, ATED and the fear of a Labour government is having a cooling effect on the market in general, but is particularly swingeing within the family house market.

“There are currently 374 houses for sale within our chosen areas and approximately 92% of them have a price tag in excess of £2m.

“It is apparent, however, that the traditional buyer of these houses is currently weighing up the situation, both political and economic, and adopting a ‘wait and see’ approach.

“What is clear is that keen vendors will need to adjust their expectations if they wish to find a buyer this summer.”

The Lonres statistics are born out by activity on Rightmove, analysed by social media expert Christopher Watkin.

He said that of 442 properties new to the market since May 19 in Hampstead, just 77 are now listed as sold subject to contract. Since the same date, 677 properties have listed in Chelsea, of which only 71 have gone under offer.

Of 234 properties in Camden, just 34 are sold stc, while in Chelsea, of 677 properties for sale, just 71 have found a buyer.

Further afield, in Richmond, of 332 properties, 65 have a buyer, while in Ealing, out of 649 properties, just 123 have found a buyer since May 19.