Thousands of people have gathered in the City of London to watch the Lord Mayor’s Show, a parade dating back more than 800 years.Alderman Nicholas Lyons marked his election as the 694th Lord Mayor of London with the traditional first official engagement of his one-year term.The Lord Mayor’s Show dates to the 13th century and includes a procession from Mansion House led by the bands of the Scots and Welsh Guards to St Paul’s Cathedral where the new Lord Mayor was blessed.Many of the City’s traditional livery companies – trade associations based on medieval worker guilds – took part.Mr Lyons then travelled in his horse-drawn state coach – the oldest ceremonial vehicle in the world still in regular use, according to show organisers – to the Royal Courts in Fleet Street to pledge loyalty to the Crown.The pageant dates back to the early 13th century and included more modern touches including the cast of the musical Grease, a gay pride float and the emergency services.