Gregory, who was the runner- last year, had a slightly better average than George with eight 180s to five from his rival, but could not match his opponent's finishing power.
George, himself a runner-up in this event in 1980, said: 'It's a lovely feeling to get this far. I never thought I would beat Mike but I told myself to have a real go.' George now meets his old rival, John Lowe, the sixth seed, in the semi-finals. Lowe, champion in both 1979 and 1987, beat Kevin Spiolek, the Cambridge left hander, 4-3 in the last quarter-final. However, Spiolek missed seven successive match darts in the fourth leg of the final set which Lowe won by five legs to three.
The other semi-final will be between Steve Beaton, the England international from Leamington Spa, and Alan Warriner, the male nurse from Lancaster.
Sixteen players including six former world champions - Eric Bristow, Lowe, Phil Taylor, Jocky Wilson, Keith Deller and Bob Anderson - have threatened to boycott next year's Championships unless the event is run by the World Darts Council, which wants to take over the professional game from the British Darts Organisation.
The top players and the WDC are upset at the poor prize-money available in the game generally and the lack of television coverage.
Lowe, the chairman of the recently formed World Professional Darts Association, said last night: 'The WDC has proved to be very effective in firstly bringing greater publicity to the game and now in creating new events.'
EMBASSY WORLD PROFESSIONAL CHAMPIONSHIP (Frimley Green): Quarter-finals: B George (Eng) bt M Gregory (Eng) 4-2; J Lowe (Eng) bt K Spiolek (Eng) 4-3.