Vets have culled 26 of the Queen's swans on the Thames at Windsor to stop the spread of bird flu.
Officials at the Department for Environment, Food and Rural Affairs called in a vet for the cull after six lifeless birds were pulled from the river earlier this month.
The 32 deaths among the 150-strong swans that belong to the Queen on a 5-mile stretch that flows around the royal estate has left Her Majesty “saddened” with many more feared at risk.
The Queen ’s Swan Marker David Barber is said to have informed Her Majesty via Buckingham Palace of the feared return of the lethal plague and she has to be kept “fully updated”.
Swan Support rescue chief Wendy Hermon, 52, is on call round-the-clock with her team both feeding the surviving swans and monitoring them on both sides of the river at Windsor, Berks.
Wendy said: “The royal flock had just recovered from the 2018 disaster when we lost about half of them but now we are right back to where we were with Avian Flu hitting them hard again.
“The Department for Environment, Food & Rural Affairs had to go into the headquarters of another rescue centre Swan Lifeline in Windsor to sadly euthanise all 26 of their swans.
“The bird flu was amongst them and they had no alternative but to put every single one of them to sleep so that they did not pass it on to the other swans that are living out on the river.
“Our job is to patrol the river and monitor the swans and so far we have had to pull out six dead ones but there are a lot more that are not doing well and we fear losing many more.
“We have lost a cygnet and a yearling and four adult swans which we found already dead in the water and we are now walking the banks and doing the best we can for the flock.
“There is nothing we can do for them they either survive the virus or they die.
“For those suffering from this disease their necks droop into the water and they leave the rest of the flock and find somewhere quiet out of the current and often just swim in circles.
“It is a nightmare and is heart breaking work and could end up being a total disaster if the virus spreads through the whole flock. The Queen is known to be very fond of her swans."
The Queen technically owns all unmarked mute swans in England and Wales in a tradition dating back to the 12th Century where they were their meat was prized for royal feasts and banquets.
Her official title is Seigneur of the Swans but she now only exercises her rights to the swans on a 80-mile stretch of the River Thames from Sunbury-on-Thames, Surrey to Abingdon, Oxon.
But she considers the swans on the 5 mile stretch which meanders down from Boveney Lock on the outskirts of Windsor around the Crown Estate land and the Castle to Old Windsor as her flock.
Swan Lifeline’s chairman Dominic Smulders confirmed that DEFRAofficials came into their rescue centre on January 3 with a veterinary surgeon to put their 26 swans humanely to sleep.
He said: “This was to prevent the swans from the lethal and horrific effects of the virus and to protect other river wild fowl from potentially catching it after cases were confirmed here.
“It has been a devastating and heart-breaking time for all of us here at Swan Lifeline and I commend our on-site team for their professionalism during these traumatic few days.
“DEFRA’s opinion was that we did everything we could to prevent an outbreak here but we are on an island and wild birds overfly us and access the pens and bring the virus in."
The Mirror has attempted to reach a spokesperson for the Queen for comment.