Last week the Queen's swans were weighed and measured. Ushma Mistry finds out why the tradition of swan-upping carries on.

A LOUD cry of "All up" is given and the six traditional Thames rowing skiffs containing an all-male crew in brightly coloured jackets, make their way to a brood of cygnets which have been sighted.

Residents along the Thames are used to seeing this traditional event, dating back to the 12th Century but many onlookers, who have stopped to see what is going on, may not know they have just encountered the art of swan-upping the annual census of the swan population on stretches of the River Thames.

David Barber, the Queen's official swan marker for the past 14 years, explains how important their role is and why they are still carrying on with the 700-year tradition.

He says: "It dates back to the 12th Century and even before that and swans are classed as a royal bird and that's why people are so interested in what we do.

"What we do is look for new cygnets and then we capture them so we can weigh and measure them and look for any injuries. We then put a small metal clasp around their feet once they have been marked and we let them go."

The Queen owns all the mute swans on certain stretches of the river Thames from Middlesex, Surrey, Buckinghamshire, Berkshire and Oxfordshire, and the ownership is shared with the Vintners' and the Dyers' companies, who were granted rights of ownership in the 15th Century.

During the five-day event the officials and crews from all three companies travel the lengths and breadth of the River Thames in the wooden skiffs adorned with their flags and pennants.

David Reed is the barge master of the Dyers' Company and has been swan-upping for the past 47 years following in the footsteps of his grandfather.

He says: "It's something that I look forward to every year. We don't always capture all of them because some of them go off downstream. I report back to the Dyers company at the end of the week. My uncle is also a swan-upper and he is 81, so it has been in the family for years."

Swan-upping traditionally takes place during the third week of July every year and most residents who live along the Thames get to see the swan markers marking the swans as they wind their way down the river.

One person who has grown up seeing images of swan-upping but never had the opportunity to see it in real life is Ben Fogle, television presenter and reality TV celebrity.

Last week, he was allowed to join the markers as they set off from the Compleat Angler in Marlow, on their way to Henley and then their final destination of the day, Sonning-on-Thames.

Ben, 31, says: "This is my first time and I am very, very excited. Swans are magnificent birds and somebody has to keep an eye on them.

"I might be able to have a go at marking a cygnet today but I have heard that they are capable of killing a man, so I am hoping they will be quite tame today."

During the five-day event David Barber and the other markers meet local schoolchildren and invite them to see what they do and explain why it is important to look after the wildlife.

He says: "I have lived in Marlow all my life and have worked on the river for most of my life. I enjoy meeting the children and telling them about life on the river and all the wildlife that we have.

"This year the number of cygnets are down because we have lost a few to shootings and some nests have been destroyed, so it is important to educate our children about the importance of looking after our wildlife."

Being a swan-marker is not an easy job as they are known to be quite violent towards humans. David says: "They are big birds. They weigh between 14 to 15 kgs and have a two-metre wing span and they are quite difficult to capture. But at the end of the day we have to do it."