Swan upping on the Thames: counting the Queen's birds – in pictures

This week marks the annual stocktake of the crown's swans on the River Thames, known as swan upping. The process of counting the swans on the river and identifying them as belonging to the Queen or one of the two City livery companies that also have rights to them - has been carried out since the 12th century, when the birds were so prized for their meat that all wild swans in England were appropriated as property of the crown. The pomp, finery and techniques of swan upping would be familiar to the villagers who looked on centuries ago