In a word, abysmal. Was very quickly replaced by Hunters.
"Tragedy began to strike early in the career of the Swift with a number of accidents involving the F 1 and F 2, one fatal. The F 1 was grounded in the August of the same year it had entered service while the F 2, which had replaced the F 1 in August, was also soon grounded. All fighter variants of the Swift were withdrawn from service by the RAF, after a short time in service, to be replaced by the more capable Hawker Hunter."
Wikipedia