As Britain continues to attract major foreign investment - including for takeover of British companies by overseas investors - new millionaires from India, China and other parts of the world are driving property prices in London.

A pad in London is avidly sought by upwardly mobile foreign entrepreneurs who see the metropolis as a safe and attractive destination. Property dealers in London have reported sales to several foreign investors whose keen interest, many say, has driven prices literally through the roof.

London is already home to 23 billionaires, 11 of them of foreign origin, including Indian steel baron Lakshmi Mittal, who has just been declared by the Sunday Times as the Business Person of the Year 2006. London is said to be particularly attractive to the global super-rich because of its accessibility, stability, low taxation and the global standing of its financial institutions. It is seen as a magnet to the world's billionaires.

London has been consistently ranked by independent studies as the best place to locate a business in Europe. One-third of the Fortune Global 500 have their European headquarters in London. Foreign owned companies account for one quarter of all businesses in London.

London is seen as the world's best gateway to international markets, including the 450 million people in the European Union, the biggest single market in the world. Many of the international companies who locate in the capital use it as their launch point for European or global expansion.

Housing industry sources say that foreign buyers bought more than half of the London homes that sold for more than ? 2 million last year.

Property developers are now working on a four-tower complex near Hyde Park, central London, which will have the world's most expensive apartment, costing more than ?20 million. The complex's security system is being laid in consultation with former army specialists.

The buyers of apartments in this tower are expected to be Indians, Chinese, Arabs and Russian billionaires. The location is a short walk from Harrods in Knightsbridge. Prices of the 80-odd flats in the tower complex are expected to be in the region of ?4,000 per square feet.

Potential buyers are being shown a marketing suite only after they show bank documents to prove that they are wealthy enough to buy such apartments.

Nick Candy, one of the two brothers who run Candy & Candy, the design company overseeing the project and its interior design, told the Sunday Times: 'This is going to be the best and most secure residential building in the world. It is for the uber-rich people who are wealthy on a global scale.'

The top 10 billionaires in London are:

Lakshmi Mittal, 55. Worth $23.5 billion. Indian. Oversees world's largest steel company.

Roman Abramovich, 39. Worth $18.2 billion Russian. Oil, aluminium, land.

Leonard Blavatnik, 48. Worth $5 billion. Russian. Oil, plastics, Warner Music.

Charlene de Carvalho-Heineken, 51. Worth $5 billion. Dutch. Inherited 25 per cent stake in Dutch brewer in 2002.

David and Simon Reuben, ages unknown. Worth $3.6 billion . British. Carpets (Simon) and property (David).

Bernard Ecclestone, 75. Worth £ 1.7 billion. British. Motor racing.

Anil Agarwal, 52. Worth $2.8 billion. Indian. Mining.

Richard Branson, 55. Worth $2.8 billion . British. Aviation and rail.

Earl Cadogan, 69. Worth $2.8 billion . British. Owns parts of London.

Bruno Schroder, 73. Worth $2.5 billion . British. Fourth generation banker.