The A41 is a trunk road between London and Birkenhead, England.Now in parts replaced by motorways, it passes through or near Watford, Kings Langley, Hemel Hempstead, Aylesbury, Bicester, Solihull, Birmingham, West Bromwich, Wolverhampton, Newport, Whitchurch, Chester and Ellesmere Port.. With the opening of the M40 extension in 1990 from junction 8, much of.