Westminster Abbey is used for state occasions
The Medieval Abbot's Dining Hall is one of dozens around London which are throwing open their doors as part of a festival to mark the Queen's Golden Jubilee.
For many years the abbey's 600-year-old hall has been a form of canteen for pupils from Westminster School who eat their meals there.
The dining hall - hidden away in a courtyard off the cloisters - still has its original timbered ceiling.
Coats of arms adorn the walls above the high table where the abbot used to sit, and the room is overlooked by a musicians' gallery dating back to Jacobean times.
The long oak tables are said to have been made from the wrecked ships of the Spanish Armada.
More than 80 other buildings along the Thames are also taking part in what is being called The String of Pearls Golden Jubilee Festival.
Cultural heritage
Others offering people a rare glimpse inside include the Foreign Office and Lambeth Palace, normally the Archbishop of Canterbury's official residence.
The festival will also feature Mansion House, Horse Guards, Marlborough House, the Royal College of Surgeons, St Martin-in-the-Fields Church and the Cabinet Office.
The "string of pearls" are hosting 400 events such as open days, talks and children's activities, offering new levels of access to Britain's social and cultural heritage.
Festival director Dylan Hammond said: "There are fantastic places in London which people rarely get to see and we wanted to open them up for the Golden Jubilee.
"They are our public institutions. They belong to us.
"We pay for them and we should know what they do.
"Our aim is to build a bridge between these conservative institutions and all sections of our society. It's about helping people feel they belong."