Double Form was a "big, strong, good-looking"[2] bay horse with no white markings bred in Ireland by his owner Baroness Thyssen.
His other progeny included Habibti, Marwell, Rose Bowl, Flying Water, Homing and Sigy[3] and he was the British Champion broodmare sire on three occasions.
In June at Royal Ascot, Double Form was moved back up to Group One level for the King's Stand Stakes, in which he started at odds of 12/1 and ridden by John Reid.
When Golden Thatch weakened a furlong from the finish, Double Form went to the front and held off the persistent challenge of Ahonoora to win by three-quarters of a length.
[9] Double Form was aimed at the July Cup over six furlongs at Newmarket, but was withdrawn after contracting a viral infection, and did not appear again until the William Hill Sprint Championship at York Racecourse in August.
He appeared to be less than fully fit and finished fourth behind Thatching, Ahonoora and Abdu, but was promoted to third after the winner was disqualified for causing interference in the closing stages.
Although the King's Stand Stakes and the Abbaye were the only two Group One races in Europe open to three-year-olds and older horses, no sprinter had previously completed the double.
Making the most of a favourable inside draw, Reid sent Double Form into an early lead and looked likely to win easily 400 metres from the finish.
[9] In 1977, the independent Timeform organisation awarded Double Form a rating of 110 p, the "p" indicating that he was expected to make significantly more than normal improvement: in their annual Racehorses of 1977, they described him as "a colt of tremendous potential".
[2] In 1979 Timeform praised Double Form for his "grit and determination" and awarded him a rating of 130, making him their highest-rated British-trained sprinter, one pound behind the Irish-trained Thatching.