The average price tag on a home has jumped to a new record high for the fourth month in a row, reaching £338,447 in July, according to a property website.
Across Britain, the average asking price is £21,389 higher than it was just six months ago, Rightmove said.
The website said the first half of this year was the busiest it has ever recorded.
With the first half of 2021 seeing 140,000 more sales being agreed and 85,000 fewer new listings than the long-term average, the surge in activity has triggered a shortfall of 225,000 homes for sale, Rightmove said.
The average number of available properties for sale per estate agency branch is at a new record low of 16 properties, compared with a longer-term average for this time of year of 31, according to the website.
The stamp duty holiday has helped to push up demand. The holiday in England and Northern Ireland was tapered from the start of July and will end this autumn.
Rightmove said detached homes with four bedrooms or more are facing the biggest imbalances in terms of demand versus supply.
These have seen a surge of 39% in the number of sales being agreed, and a drop of 15% in the number coming to market when compared with the first six months of 2019.
The company added that, more positively, first-time buyers will find that their typical sector of properties with two bedrooms or fewer has virtually the same supply levels as in 2019 and the stock shortage is less acute.
Tim Bannister, Rightmove’s director of property data, said: “First-time buyers are currently benefiting from their sector having the most buyer-friendly conditions.
“Choice is still more limited when compared to the same period in 2019, but price rises are the most subdued of any sector. Saving a deposit is still very hard, but 5% is now an option, and, with many paying rising rents, buying your own home on a lower deposit is becoming an opportunity again.”
Marc von Grundherr, director of Benham and Reeves estate agent, said: “There’s no doubt the stamp duty holiday has been the catalyst for this impressive market performance.
“However, it isn’t the driving factor behind the intent to purchase for UK home-buyers and so a robust level of activity will remain long after it has expired.
“When you couple heightened demand with a severe shortage of stock, it’s very likely that property values will remain buoyant for the remainder of the year, at the very least.”