No, they're not Britain's Royal Family but embassies from around the world, many of which are housed in some of the grandest buildings on the most exclusive streets in London, can fetch a pretty penny on the property market.

In a first, London property consultancy Lichfields together with Spear's magazine, went ahead to value 186 embassies in the British capital.

Assuming that each of the buildings they occupy is owned freehold and has residential use, their total value came out to a whopping 4 billion pounds (S$8.2 billion).

Here are 5 other interesting finds:

1. The most expensive

No surprise perhaps but it's the United States' massive new embassy - complete with moat - being built in Nine Elms at a cost of 600 million pounds.

The US embassy's current site on Grosvenor Square was sold to Qatar's sovereign wealth fund for 500 million pounds.

Nine Elms in central London - once a semi-derelict, light industrial zone - is undergoing a mulit-billion pound transformation into an ultra-modern residential and business distinct.

The new US embassy will be one of the area's three iconic attractions, the others being a regenerated Battersea Power Station and the New Covent Garden Market.

2. The cheapest

North Korea's embassy in a semi-detached house in Gunnersbury, a suburban district of west London, is worth just 750,000 pounds.

It is notable for being one of the few embassies in London located in a suburban area, away from the traditional diplomatic enclaves like Belgrave Square and Kensington Palace Gardens.

3. Rent: 1 pound a year

Russia rents its embassy, Harrington House, from the UK government but although it is on Kensington Palace Gardens, one of the world's most expensive roads, for only 1 pound per year.

This is thanks to a 1991 agreement whereby the UK in turn pays only one rouble a year for its embassy in Moscow.

4. Size of economy relative to value of embassy

As expected, the richer the country, generally the more expensive the embassy it occupies. Thus countries like the US, Canada, Saudi Arabia, Australia and Japan have properties worth over 100 million pounds each.

Interestingly, the Chinese embassy, which occupies a corner building on the best street in Marylebone, is thinking of moving to Nine Elms too.

But there are some poorer countries which buck the trend. For example, Malta which has a GDP (gross domestic product) of US$8.69 billion, compared to Singapore's US$276 billion, has a huge building on Piccadilly worth around 20 million pounds. Similarly, Lesotho has a GDP of only US$2.44 billion but an embassy on Chesham Place, worth at least 5 million pounds.

Syria's embassy on Belgrave Square, one of the grandest and largest 19th-century squares in London, could fetch 30 million pounds if it were to be sold.

5. Singapore's embassy is relatively modest at 25 million pounds

It is located at 9 Wilton Crescent, Belgravia, with the Luxembourg embassy up at No. 27. Northwest to it is posh Belgrave Square, boasting several other embassies.

In the 19th and 20th century, Wilton Crescent was home to many prominent British politicians, ambassadors and civil servants.

Lord Louis Mountbatten (1900-1979) - who as Supreme Allied Commander of South East Asia received the surrender of Japanese forces in Singapore during World War II - lived at 2 Wilton Crescent for many years.