 This study is a multi-centre, randomised, double-blind, placebo-controlled with rescue medication, two period crossover study in subjects with persistent uncontrolled asthma, currently not treated with an inhaled corticosteroid ICS or long acting beta 2 agonist LABA. This study is the first administration of GSK2269557 to asthmatic subjects, and the aims of the study are to investigate the efficacy, safety, tolerability, and pharmacokinetics of four weeks of treatment with orally inhaled GSK2269557 1000 microgram mcg in subjects with persistent uncontrolled asthma. In a sub-study, biological mediators will be measured from induced sputum and blood. 