Young wanted to head his own force and tried to become chief constable of the Isle of Wight Constabulary , before he became Acting Chief Constable of Leamington Spa Borough Police in September 1938 , aged 31 , at a salary of Â # 500 per annum . Young wanted to head his own force and after one unsuccessful attempt ( for the chief constableship of the Isle of Wight Constabulary ) , he became Acting Chief Constable of Leamington Spa Borough Police in September 1938 , aged 31 , at a salary of Â # 500 per annum .