Nils Taube was Britain’s longest-serving fund manager. A former adviser to Lord (Jacob) Rothschild and a colleague of George Soros, he delivered an average annual return of 15 per cent a year over the 35 years that he ran his own fund, and had a ringside seat at most of the financial crises of the past four decades: the slump of the early 1970s, the 1987 crisis and the 2000 technology crash.

He was born in Estonia in 1928 to an English mother and a father who was a member of the “Baltic Barons”, the region’s upper classes. The family fled to Germany when the Soviet Union occupied Estonia in 1940, and Taube went to school in Germany during the war. Friends said he remembered how compassionately he was treated.

He arrived in Britain in 1946 and joined the stockbroker Kitcat & Aitken two years later.

William Rees-Mogg, the Times columnist who first met Taube when he was a junior partner at Kitcat in the early 1950s, said: “German shares were very undervalued in the 15 years after the war. English brokers didn’t know anything about them, but Nils did. As the German economy recovered, there were some real opportunities to make some very sensible investments.”

Taube received an early pay rise for realising that the Anglo-Iranian Oil Company, later to become BP, could recover from the nationalisation of its Iranian assets with a refinery in Aden.

Taube worked his way up the compay, becoming a senior partner in 1975. It was at Kitcat & Aitken that he worked on an issue of British gilts for George Soros, making the trader so much money that he was invited on to the advisory board of his Quantum Fund. When Kitcat was taken over by Rothschild’s firm RIT and Northern in 1982, Taube became principal investment adviser to Rothschild’s group of companies.

Colleagues said that Rothschild bought Kitcat mainly so that he could “get hold of” Taube, who had made a name for himself by keeping his head during the slump of the 1970s. He relished telling the story of how, in 1974, City friends called him “irresponsible” for spending the last £2,000 of his children’s trust fund on shares such as Hoover and Shell. They subsequently went up more than 125 times.

Rees-Mogg said: “I was working at the Financial Times at the time, and was close to the people who wrote the Lex column. They thought he was an extremely gifted investor. Even in tough times he was relatively optimistic. I remember in the 1970s when everyone thought the world was ending, he would explain why that wouldn’t happen. He was not a doom and gloom merchant — he was extremely good at spotting the bottom of the market and investing at that time.”

Taube is perhaps most famous for anticipating the stock market crash of 1987. He had been shorting stocks — selling in expectation of a fall in prices — for several months before the crash, which initially led to heavy losses. By December, though, he had made a profit of £75 million.

Friends said that his secret was buying stocks that had been overlooked by other investors.

Taube ran his own fund from 1969 until 2006, consistently outperforming the market. Retirement was not an option for Taube, who said that investing was “like being paid for doing the crossword”. At 79 he was still taking an active role in day-to-day fund management and was building up a new business, Nils Taube Investments. He was taken ill last week while sitting at his Bloomberg terminal at 7.30 in the morning, checking the previous day’s market data.

He is survived by his wife and three sons.

Nils Taube, fund manager, was born on July 25, 1928. He died after a stroke on March 11, 2008, aged 79