Middle of an upgrade cycle/paralysed by political interference and traditional british design conservatism verging on incompetence
The Hunter eventually became "superior", but took many years to get right,
after it entered service with the RAF. For example, if that airbrake under the rear fuselage looks added on as an afterthought, that's because it essentially was. Early Hunters also suffered the unfortunate handicap of the Avon being prone to surges and stalling due to gas ingestion when the guns were fired, among other problems. Firing the guns was actually forbidden for a time on a fighter
in frontline service until a fix was found. Even if ready in 1951, they weren't fit for combat. It would take until 1956 or so until that kind of point was reached.
And we shouldn't forget about it's contemporary the Supermarine Swift either. Or maybe we should. Great tactical reconnaissace machine. Pity it was designed as a fighter

Postwar British fighter design makes for somewhat depressing reading.