White sugar did its best to fulfil a forecast of a "fireworks display" after an executive at Cosan, the world's top cane processor, stoked fears over supply hiccups by saying the queue of vessels at Brazil's ports had reached record length.

"We haven't stopped loading ships for one minute, and still I have never seen a line-up of vessels like this," said Julio Fontana Neto, the chief executive officer of Cosan's logistics unit Rumo Logistica.

Shipping agencies say the number of vessels waiting to load at six Brazilian sugar ports has topped 100, from around 90 two weeks ago.

Mr Fontana's comments fuelled concerns that Brazil, which is responsible for more than one-half of world sugar exports, would be unable for now to meet the immediate demand from countries which let stocks run down rather than buy at record prices earlier in the year.

New York's October raw sugar contract rose by 0.8% to 17.2 cents a pound, taking its gains over the last six trading sessions above 13%.

However, white sugar, which as refined product is better able to meet emergency needs for the sweetener, did better on the day, rising by 2.9% to $606.80 a tonne for August delivery in London, a four-month high for a near-term contract.

The slightly better-trade October lot jumped 4.5% to $535.00 a tonne at one stage.

'Jittery shorts' 

Indeed, Thomas Kujawa, at Sucden Financial Sugar, had earlier in the day braced investors for a "fireworks" display as supply fears combined with the imminent expiry of the August lot, limiting investors' opportunity for covering short positions.

"Further talk of port congestion gives the shorts the jitters," he said, noting that, with more than 8,000 contracts still  left open, a relatively large amount so near to a contract's demise, funds were still active in the contract.

"Funds lucky enough to be left in may leave it till the last moment" to shift position to the October lot, given the widening gap between the two contracts.

The premium of the August contract over October topped $82 a tonne on Thursday to reach what Mr Kujawa told Agrimoney.com appeared to be a record.

Market squeeze?

He added that the relative strength of London's August sugar lot showed signs of a market squeeze, in which a player corners a large chunk of available contracts, forcing other investors to pay up to win supplies.

The comments come as cocoa industry groups are pressing London's futures exchange for increased regulation, to curb the speculators they claim have driven undue strength in short-term prices of the bean.