Urethrocystometry was performed during a provocative handwashing test in 163 patients, 115 of whom had a prior history of urge incontinence. Almost invariably, a rise in detrusor pressure, when present, followed a fall in urethral pressure, and both were preceded by urge symptoms. This pattern appears to conform to the concept of "urethral instability", "detrusor instability" and urge incontinence being different manifestations of a prematurely activated micturition reflex.