With a single small deal, an independent trader yesterday secured his place in market history by pushing oil prices briefly to the unprecedented level of $100 a barrel, writes Javier Blas.

Some observers questioned the validity of the price mark when it emerged that the peak was the result of a trader - one of the "locals" who trade on their own money - buying from a colleague just 1,000 barrels of crude, the minimum allowed, industry insiders said. The deal on the floor of the New York Mercantile Exchange was at a hefty premium to prevailing prices.