Sales of homes worth more than £1 million have plunged by nearly a fifth year-on-year, Land Registry figures show.
Across England and Wales, 851 homes were sold for over £1 million in January, a 19% fall compared with January last year, when 1,049 properties in this bracket were snapped up.
The bulk of transactions involving homes worth more than £1 million were in London, which saw a sharp 23% decline in sales in this bracket compared with a year earlier.
Some recent reports have suggested that political uncertainty, with the possibility of a mansion tax, and affordability pressures have been taking some of the steam out of the property markets in London's most expensive boroughs.
Stamp duty changes in December have made the tax more expensive for some buyers purchasing high-end homes. While the tax has become cheaper for the majority of buyers liable to pay it, the tipping point comes when homes are worth more than £937,500.
The Land Registry's figures show that house prices in Kensington and Chelsea, where the average property is worth £1.29 million, have shown the slowest annual growth over the last year of all the London boroughs, recording a 5.2% upswing.
Westminster was the only other London borough to see year-on-year price growth below 10%, with a 9.9% increase taking the average value to £999,687.
By contrast, Newham, where the average home has a value of £291,364, saw the highest growth of the London boroughs, recording a 19.8% increase.
Matthew Pointon, a property economist at Capital Economics, said: "Uncertainty regarding the mansion tax has taken its toll on prices in prime central London."
Across all price brackets, the number of completed house sales in England and Wales in January stood at 53,168, an 18% fall compared with 65,175 in January last year.
Property values increased across England and Wales by 5.3% over the year to March to reach £178,007 on average and on a month-on-month basis they dipped slightly, by 0.8%, the Land Registry said.
Semi-detached homes have recorded the strongest price growth over the past year, adding 6.1% to their value. A typical semi-detached home is now worth £169,194.
At a regional level, London continues to record the strongest year-on-year price growth, with a 11.3% increase taking the average house price in the capital to £462,799 in March.
The North East was the only region where average house prices were lower than a year ago, with a 2.9% fall taking the figure to £97,444. In Wales, prices recorded a 2.7% year-on-year increase to reach £117,828.
The figures were released as estate agents across the UK reported a lull in the market as house hunters await the outcome of the General Election, with the first-time buyer market in particular seeing a dip.
Less than one in four homes sold in March went to first-time buyers, according to the National Association of Estate Agents (NAEA). Its figures showed that 22% of house sales in March involved people taking their first step on the property ladder, down from 30% in February.
Overall, the NAEA said that demand for property is the lowest in a year. An average of 343 house hunters were registered per branch in March, down from 366 in February.
Nearly two-thirds (63%) of estate agents reported a slowdown in the market as the election approaches, the NAEA said.
The NAEA said the supply of homes on the market has edged up to an average of 48 per estate agency branch, compared with 43 in February.
Mark Hayward, managing director of the NAEA, said: "We may have seen a slight increase in supply this month, but it is not an ongoing trend or a big enough jump to fill the gap for demand.
"Although our agents have seen the market cooling off ahead of the General Election, it will inevitably bounce back again at a rapid rate after May 7, so it is more important than ever that the party elected focuses on increasing the supply of homes."
In Scotland, Edinburgh is seen as a city with huge growth potential. In 2014, prices in Edinburgh were up 10% in a post referendum boom that shows little sign of slowing down.
Local agents are not expecting quite such stellar growth for the next 12 months, but they think price rises will be well above the average predicted for the whole country.
Rightmove named this as the area where it expects house prices to grow the most over the next five years. It says that over this period there will be a huge number of people moving out of London in order to afford to get onto the property ladder. They want a reasonable commute combined with plenty of attractions in the local area, and Southampton offers all this. With relatively affordable housing stock, it's a prime candidate for growth.
Luton was Rightmove's candidate for the second biggest house price rises over the next five years. It emphasised that this isn't a mater of opinion, it is the result of crunching the data.
Luton is another major beneficiary of the move out of London, and while it is arguably not as attractive a place to live as Southampton, it's only 23 minutes into central London - which rivals some of inner London's commuter times. With average prices of £179,368, it's clearly a far more affordable option, and the area has already started to show signs of a boom.
This was the third area suggested by Rightmove. As with Southampton, it is well positioned for London commuters, and also has huge local attractions.
A survey last year asked young professionals to name the place they would most like to live, and Brighton and Hove were the only areas that appeared on the list outside London.
One of the reasons it's not higher up the list is that houses are already on the pricey side, with an average cost of £338,956 - up 13% in the past year alone.
There may be few people who grow up with the dream of living in Swindon, but the electrification of the rail line to London will bring travel times down across the West Country, so Swindon becomes part of the outer commuter area.
Given that the average property costs £168, 968, it's easy to see why Swindon will be a popular option for commuters on a tight budget.
Bath is also going to benefit from electrification of the line, because the commute to London will fall to a manageable 70 minutes. The beauty of the city - along with a vibrant social and cultural life - makes it a clear choice for more long-distance commuters.
Of course, with an average asking price of £374,617, it's not a tremendously cheap place to buy, but the geography of the city restricts development, so these prices are expected to rise still further.
Property Frontiers says that the booming house prices in Oxford are set to get even higher. At the moment, travel to London takes 60 minutes, but this will reduce even further in 2016 when the line is electrified. Prices in the most desirable parts of the centre aren't much cheaper than London.
However, further out there are pockets of affordability, and when the Water Eaton station opens in 2015 it will open up areas to the north of the city too.
Manchester has seen enormous property price rises over the last couple of years, and Property Frontiers expects this to continue into 2015.
Other commentators are expecting the growth to slow over the next few years, especially given the gains made since 2012. However, demand for properties remains buoyant, and with the growth of the local economy, price rises seem inevitable.
Rising prices in London have pushed buyers further and further out of the centre, so estate agents are now claiming zone three as 'the new zone 2'.
Savills believes that the biggest gains over the next five years will be the less glamorous districts - putting the South and East in the frame. Gritty areas that could benefit include Ladywell, Streatham and Catford in the south, and Leytonstone, Forest Gate and Walthamstow in the east.
Cambridge could also perform well. It has already had house prices lifted by the growth of tech companies to the north of the city, and the arrival of pharmaceutical headquarters will help push prices up further.
In 2016 a new rail service from the city to the science park will keep prices rising, and beyond the opportunities presented by the local economy, Cambridge is also part of the 'outer commute' area of London, which Savills expects to shoot up in value over the next five years.