Prices of the UK’s most expensive homes have fallen for the second month in a row, according to the latest Prime Property Index from PrimeLocation.com.

The monthly index tracks the top 25% of the UK market by asking price. It reveals that prime asking prices have fallen 1.3% over the past couple of months, taking an average of £6,234 off the asking price of these homes over the summer.

In July, prime asking prices fell 0.5% and in August prices declined by a further 0.8%. This brings the current average asking price of UK prime homes to £476,302.

Prime asking prices in five of the UK’s 11 regions fell in July and in August nine of the 11 UK regions experienced this decline. Yorkshire and the Humber is the only region that experienced prime price growth in the past two months, equivalent to just 0.1%.

Despite this two-month decline, prices of prime homes for the UK as a whole are still 1.3% higher than this time in 2011, although this year on year increase has been getting smaller. In April, the price of prime homes was 4.8% higher than they had been 12 months before this, but this year on year increase has become gradually smaller every month since.

“The market for the UK’s most valuable homes is a resilient and healthy one, which is why this mid-year fall in prices is worth taking note of,” said Lawrence Hall of PrimeLocation.com.

“Owners and potential buyers of the UK’s Prime homes will be keeping an eye on price movements over the coming months as we discover whether this fall in asking prices is a temporary summer lull or whether this is actually sellers getting ready and adjusting prices for the September market.”

Meanwhile, London’s prime asking prices fell for a second consecutive month in August, with this two-month decline wiping £13,997 off the value of London’s most-desired homes. In July prime prices fell 0.2% and in August they fell 0.9%, bringing the average asking price for a Prime home in the capital to £1,326,716.

In August, 11 of 16 boroughs tracked by the index saw prices fall, while in July 8 of the 16 saw prime prices decline.