These prestigious shows are run by Thorough Events Ltd, of which Iain Campbell is the CEO. http://concoursofelegance.co.uk/
The first was staged at Windsor Castle in 2012, to celebrate the Queen's Diamond Jubilee. This presented 60 of the world's finest cars on display, including the Queen's Rolls Royce Phantom VI Canberra. Prestigious Classic car clubs were invited to display members' cars along the Long Walk, and Aston Martin, Jaguar and Bentley were among the exhibitors.
As a result of huge demand, and by invitation of the Royal Family, the event was staged at St. James Palace in 2013, and included a road run to the venue. Hampton Court followed in 2014, Holyrood House in Edinburgh for 2015, with a return to Windsor Castle in 2016.
Each year, the format is the same; 60 of the world's finest cars are displayed as a centrepiece, many taking part in a local street tour, and an overall winner is judged. Selected clubs are invited to provide high quality cars for Club Displays, as part of the overall show, and are invited to provide their best Concours winner to compete for the Club Trophy.