Homes in Westminster in central London are the most expensive per square metre in the UK - and the most cramped - a study has found.
Properties in the heart of the English capital cost £7,586 per square metre on average and are typically 71 square metres in size, making homes in Westminster the tiniest on average in the country, Halifax found.
St Albans was named the next most expensive city, with homes setting buyers back £3,227 per square metre, almost double the UK average of £1,668.
Oxford, Winchester, Chichester and Cambridge are also among the most expensive areas, while Edinburgh is the only city among the top 10 based outside southern England.
York was named as the most expensive city per square metre in northern England, with homes costing £1,830 per square metre.
Martin Ellis, housing economist at Halifax, said: "House price per square metre is a useful measure for house price comparison because it helps to adjust for differences in the size and type of properties between locations...
"Westminster has the most expensive prices in the UK on a price per square metre. Interestingly, it also has the smallest average property size in the country.
"Not only has Westminster got one of the highest population densities per square kilometre among UK cities, but it also has a large proportion of properties that are flats."
With a value of £817 per square metre, Londonderry was named as the UK's least expensive city, followed by Lisburn, Hull, Bradford and Swansea.
Armagh in Northern Ireland was found to have the largest average property size in the UK, at 153 square metres.
Meanwhile, properties in the town of Ellon in Aberdeenshire have recorded the largest gain based on the average price per square metre over the last decade, with a 169% increase to £2,022.
Halifax said that other areas of Aberdeenshire such as Fraserburgh, Peterhead and Inverurie have also seen big increases over the last 10 years, largely driven by the booming oil industry as a key part of the local economy.
Halifax calculated the figures from its own database.
Here are the most expensive cities based on price per square metre: 1. Westminster, London, £7,586 2. St Albans, South East, £3,227 3. Oxford, South East, £2,821 4. Winchester, South East, £2,813 5. Chichester, South East, £2,638 6. Cambridge, East Anglia, £2,634 7. Brighton, South East, £2,549 8. Bath, South West, £2,376 9. Edinburgh, Scotland, £2,125 10. Salisbury, South West, £2,060
Here are the least expensive based on the price per square metre: 1. Londonderry, Northern Ireland, £817 2. Lisburn, Northern Ireland, £945 3. Hull, Yorkshire and Humberside, £1,027 4. Bradford, Yorkshire and Humberside, £1,042 5. Swansea, Wales, £1,063 6. Belfast, Northern Ireland, £1,064 7. Durham, North, £1,104 8. Stoke On Trent, West Midlands, £1,126 9. Sunderland, North, £1,129 10. Newport, South Wales, £1,134