Where is the oldest door in Britain?

Britain's oldest door can be found in Westminster Abbey, in the passage leading to the Chapter House.

The door is made of five vertical oak planks held together with three horizontal battens and iron straps. The battens are recessed into the planks so that the door is flush on both sides: usually medieval doors have a flat front and the back has projecting ledges and braces. The construction of this door is unique and shows that it was intended to communicate between spaces of equal importance in the Abbey. However, its original position is unknown. The boards are from a single tree and rings on them show growth during the years from AD 924 to 1030. As the bark was trimmed when the planks were made into a door it means the exact year of felling cannot be known.

The door was dated for the first time in 2005 using dendrochronology. A detailed study of the wooden door, which can be seen in the vestibule leading to the Chapter House at Westminster Abbey, showed that the wood was felled after 1032 AD and that the door was constructed sometime in the 1050s. This was during the reign of King Edward the Confessor, who built the Norman Abbey which was consecrated in 1065.

That makes it not only the oldest in the UK but also the only one assignable to the Anglo-Saxon period. The ring-pattern of the timber indicates that the tree grew in eastern England, most probably coming from the extensive woodland owned by the Abbey in this area, and possibly from Essex.