They said the details of the unusual sales were difficult to confirm, but most estimated that trader Arcadia had sold five million barrels of the North Sea crude into China and Singapore from South African storage tanks.Most of the crude is expected to arrive in Asia in March and traders estimated that Arcadia's storage in South Africa was now cleared out of Brent.

Arcadia, a London-based affiliate of a Japanese trading house, declined to comment about the Brent trades.

Traders doubted that any of the buyers were adopting a fresh strategy to bring Brent to Asia consistently, or that sellers were looking to lock in long-term sales of Brent to Asia.

Instead, they said when the near months in the Brent market flipped into backwardation in December it gave Arcadia the opportunity to push out the crude into themarket.

Traders said that assuming Arcadia had locked in the inter-month contango spreads when it purchased the barrels mid last year, the sales of the Brent to Asia would have been profitable.

"When they bought the barrels, they would probably have done some inter-month spreads," said a western trader. "These spreads would now have appreciated quite a bit, so I'm sure they've made a profit," he said.Traders said Arcadia was seen buying at least eight million barrels of physical Brent in July last year.

But traders said it was reasonable to assume that the incentive for Arcadia to sell the cargoes only came in the last month, as the market flipped into backwardation.

The Brent price structure remains backwardated to March, before the curve swings back into contango.

Traders said Arcadia's Brent cargoes were heard sold at prices equivalent to a $1.00-per-barrel premium to Dubai quotes.

Traders, however, added that the actual price was probably of little significance to the totaltransaction.

"They (Arcadia) are probably making money simply from the spreads, so what they actually sold the cargoes at wouldn'T make a big difference," said a trader.

"And selling it to Asia was just because there was a buyer there," he said.A source at Chinese trader Unipec confirmed the company had purchased around four million barrels for arrival in March, but the source declined to give further details.

Traders said apart from the cargoes known to be heading east, Arcadia had also committed the rest of the Brent supplies from the Saldanha Bay storage, to undisclosed destinations.