* Brent net longs down 25 pct as prices fall to 3-month low
* ICE gas oil net longs cut by 20,028 to 34,551
* ICE data confirms extent of fund unwind during price rout
* Brent ICE data graphic: link.reuters.com/jus96s
* Gasoil ICE data graphic: link.reuters.com/puk69t (Adds graphic link, details)
By David Sheppard
LONDON, July 21 (Reuters) - Hedge funds and other large speculators slashed their bets on higher Brent crude oil prices by almost 25 percent in the week to July 15, ICE said on Monday, as prices collapsed to their lowest in three months.
The IntercontinentalExchange Inc. said money managers reduced their net long futures and options positions in Brent to 151,981 from 201,568 as prices fell to a three-month low of $104.39, down from more than $115 a barrel in mid-June.
Hedge funds have now reduced their Brent bets by almost 40 percent since late June, when they accumulated a record position as the advance of Islamist insurgents in northern Iraq threatened to disrupt oil supplies from the OPEC country.
But weak demand in physical markets triggered a rapid 10 percent correction in Brent after no serious oil disruptions emerged, leaving many funds nursing painful losses.
The move was mirrored in the New York Mercantile Exchange (NYMEX) U.S crude oil contract, where big speculators closed out nearly $6 billion worth of bullish bets last week, confirming the biggest four-week fund exodus on record.
Brent prices for immediate delivery came under additional pressure last week, with the spot market falling to a steep discount compared to contracts for delivery in later months - a market structure known as contango that indicates weak demand.
On Monday Brent was trading just below $107 a barrel, having risen slightly from last week's lows as tensions increased between Russia and Western powers over the downing of a Malaysian passenger plane in Ukraine.
The ICE gas oil contract, which is used for hedging against and speculating in price moves linked to diesel, jet and heating fuel, also saw an exodus of funds last week.
Data from ICE showed hedge funds and other large speculators cut their net long futures and options positions in gas oil by 20,028 to 34,551, a decline of 37 percent.
ICE gas oil has also slipped into contango, encouraging traders to store diesel and jet fuel until prices recover, with gas oil stocks in independent storage in the Antwerp-Rotterdam-Amsterdam hub steadily rising over the past two months.
Gas oil fell to a 13-month low of $871.50 a tonne on July 15, 7 percent below a three-month high of $943.75 in June. (Reporting by David Sheppard; Editing by David Goodman and David Evans)