FOR an oligarch nervous about the future, it is the ideal bolthole. A Russian billionaire is spending tens of millions of pounds building a high-security “KGB-proof” mansion in Surrey.

Peter Aven, head of the biggest private bank in Russia, is said by locals to have surrounded his 8.5acre property on the Wentworth estate near Virginia Water with “intelligent” electronic fencing and incorporated a bombproof shelter in the design. It also has a two-storey octagonal guardhouse by the main entrance.

The property, Ingliston House, has been designed by Robert Adam, a firm of classical architects also employed by Prince Charles. It has been fitted out by Nicky Haslam, the interior designer, who said it was a “wonderful building”. Construction is likely to be finished within the next few months.

One resident at Wentworth said: “Contractors are telling us the latest installations have included £1.5m worth of an elaborate wiring system to keep the building ‘fortress-secure’.”

Aven, 52, and his wife Elena, a historian, bought the site of Ingliston House for £8.55m in 2004. Construction has so far cost at least another £15m.

The couple are believed to be building the house as an “insurance policy” in case they and their two children have to flee their homeland.

Aven’s business empire is centred on Alfa-Bank, the biggest private finance group in Russia, of which he is president. But it is seen as highly vulnerable as factions jostle to secure the succession to Vladimir Putin, the country’s leader, who is due to step down next year.

The security measures at Ingliston House are increasingly seen as “standard fittings” for Russian exiles in Britain who are fearful after the death of Alexander Litvinenko, the former spy, last November.

Litvinenko, poisoned with radioactive polonium210, is widely believed to have been murdered either on Kremlin orders or by former agents of the FSB, successor to the KGB.

Residents on the Wentworth estate include Andriy Shevchenko, the footballer, and Bruce Forsyth, the television presenter. From 1998 to 2000, Augusto Pinochet, the former Chilean dictator, was kept under house arrest on the estate. It is now home to Boris Berezovsky, the refugee oligarch who was Litvinenko’s employer in Britain.

Berezovsky takes elaborate precautions. According to locals, when he leaves his 240-acre property, Wentworth Park, four identical limousines peel away in different directions to confuse would-be attackers.

Berezovsky, who was close to Peter Aven in the early 1990s, lives only 500 yards from Ingliston House, which borders the fourth fairway on Wentworth’s championship golf course.

In contrast to the opulence of other oligarchs, the design chosen by Aven is austerely classical, inspired by Palladio’s Villa Rotonda near Vicenza. The house will have just six bedrooms in its 29,000 sq ft. The plans show suites designed for “grandparents” and a wing dedicated to the indoor pool.

Details are not known of Aven’s explosive-proof “panic room”, where the family would retreat in the event of an attack by hitmen. But it is likely to have its own air supply as well as food and water for 30 days.

Systems to detect intruders, controlled from the property’s own security room, are likely to include “active infrared” beams which form a a mesh around the perimeter and detect motion when a beam is broken. They may also feature microphonic cable that detects both sounds and vibrations from walking.

Peter Clements, a consultant with Templepan security, a VIP protection specialist, said: “Typically, perimeters like this are divided into sectors and whenever movement is detected the CCTV camera on that sector automatically comes up on the operator’s screen. They can then decide whether it is a false alarm or something suspicious.”

Aven, who has the world’s biggest private collection of Russian art, served as a minister under Boris Yeltsin in the early 1990s before helping set up Alfa Group, his bank’s parent company. He is estimated by Forbes magazine to be worth more than £1.5 billion. His empire includes the Russian half of a joint venture with BP.

Alex Goldfarb, a friend of Berezovsky, said: “The only person protecting Alfa from the hungry clique of FSB generals is Putin because of his special relationship with BP, so who knows what will happen after he goes.”

Aven declined to comment.

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