The move is being seen as a thumbs up for the UK property market from Mr Soros, a speculator who inspires legions of copycat investors the world over.
Quantum Realty Fund, which is managed by Soros Fund Management, is to take a controlling shareholding in Delancey Estates, a hitherto little- known property company. Shares in Delancey leapt by almost 50 per cent at the news to close at 150p, up 47.5p.
Although Quantum will provide financial backing for Delancey, management for the property company will be provided by Freehold Portfolios Estates (FPE), a property advisory company owned by James Ritblat, son of John Ritblat, the formidable chairman of British Land. Delancey is to buy FPE in a deal which could net Mr Ritblat Junior as much as pounds 4m in Delancey stock.
James Ritblat will become managing director of the new Delancey Estates. Colin Wagman, Delancey's current chairman, is expected to step down once the deal is completed in early July.
Mr Wagman said: "These proposals will transform Delancey's profile and the opportunities available to the company."
Quantum Realty is investing pounds 100.5m in Delancey, a sum which will give it a 66.7 per cent stake. Delancey plans to raise a further pounds 28m via a share issue.
James Ritblat will have to cope with some interesting shareholder dynamics in his new role. His father currently holds 27 per cent of Delancey , although this stake will be diluted to just under 7 per cent once the Quantum deal goes through.
"Its a bit of a tricky proposition, isn't it", said Mr Ritblat of his father's stake in Delancey. "We'll just have to see how it goes."
The Quantum-Delancey-FPE deal cements years of co-operation between the Ritblat and Soros families. Quantum Realty and British Land embarked on a joint venture between 1992 and 1994, an initiative managed by James Ritblat.
The joint venture was brought to an end "amicably" in 1994 after Quantum decided to "reallocate its assets", according to one source. But James Ritblat evidently managed to impress the powers that be - his company FPE now manages a property portfolio for the Soros family.
Mr Wagman said he initiated talks with Quantum, which was more than happy to invest in Delancey as long as it had the right management team.
Given Mr Soros's links with the Ritblat family, FPE seemed the natural place to turn for managerial input, Mr Wagman said.
James Ritblat will be joined on the Delancey board by Richard Katz, Quantum Realty's chairman, and Martin Edelman, real estate adviser to Soros Fund Management. The company is looking for another three non-executives.Reuse content