Traditional swan counting takes place on the River Thames

The centuries old tradition of Swan Upping is underway along the River Thames, with adjustments made this year because of the heatwave.

The Queen's Swan Marker, David Barber, accompanied by his team of Swan Uppers, has taken to the water in traditional rowing skiffs.

They began on Monday and will finish on Friday at Abingdon Bridge in Oxfordshire.

Usually, the baby swans would be removed from the water and taken ashore to be weighed, measured and examined for any problems.

But because of the temperature, the cygnets were only checked in the boats for health issues and promptly returned to the river to keep cool.

The Swan Upping ceremony dates back to when the ownership of all unmarked mute swans in Britain was claimed by the Crown in order to ensure a ready supply for feasts.

It is the duty of the Queen's Swan Marker to count the number of young cygnets each year on certain stretches of the Thames and its surrounding tributaries, and to ensure the swan population is maintained.

Its focus now is conservation and education.

Mr Barber said "The cygnets do have an issue of going into fishing lines because they're not streetwise or riverwise so you have to check those over."

"Normally, we would take them out of the water ashore and weigh each cygnet and measure each cygnet for our data."

Mr Barber said the number of cygnets appears to have fallen, but it is not a cause for concern, with numbers expected to drop due to the impact of avian flu.

One crew member held up an umbrella to protect himself from the soaring temperatures as one of the boats made its way along the river.

Others took a break from rowing and relaxed, lying down in the boats amid the sunshine.

The Queen retains the right to claim ownership of unmarked mute swans swimming in open waters, but this right is mainly exercised on certain stretches of the Thames, with the ceremony dating back to the 12th century.