London 2012 Olympics: Mayor of London Boris Johnson's 8,000 strong volunteer army for Games Quite how visitors to London, especially the shy and reserved among them, will react to the offer of advice from a volunteer dressed up like a butcher with a penchant for purple remains to be seen, but Mr Johnson believes they will help make 2012 a "summer like no other." Speaking at Wimbledon train station, Johnson also revealed that a two-week public exhibition has been opened at City Hall to give Londoners an idea of how the capital will look and feel during Games time. But if the unveiling of the Boris Pods and uniforms is anything to go by residents should be braced for parma violet bunting. Guide What will the ambassadors do? They will be the first point of contact for visitors to the Games, offering advice and guidance to visitors and Londoners as they negotiate the city. They will work five-hour shifts for up to six consecutive days. Where will they be based? Around London at one of 43 visitor locations including landmarks, hot spots and travel hubs, including Trafalgar Square, Oxford Street and Wimbledon. What are they wearing? A polo T-shirt, trousers, jacket and bag, as well as a trilby hat. All in various shades of purple.