Following an initial screening at the screening visit(Visit 1), patients enter a 2 week run-in period. Patients are allowed to take salbutamol (Ventoline, Diskus, 0.2 mg) prn as rescue medication and have to record their daily use of it on the Patient's Diary. Patients who meet all inclusion and none of the exclusion criteria at the check at Visit 2 will be randomised thereafter into the randomised treatment period of the study during which they will receive either tiotropium(Spiriva) or placebo in blinded fashion.