Supertri Blenheim Palace will take place in the grounds of the estate on June 6 and 7, offering the world’s only swim-bike-run festival set against the backdrop of a UNESCO World Heritage Site.

More than 7,000 participants are expected to take part across a weekend of racing in the birthplace of Sir Winston Churchill.

Gemma, a mother of eight-year-old twins, will compete in her first triathlon despite a lifelong phobia of water.

Gemma, 41, from Swindon, said: “I want to prove to my twins that you really can do anything you set your mind to.

“What better way to show them strength than by pushing myself outside my comfort zone?”

Her journey to this point has included losing 10 stone and a long IVF journey with her wife before having their twins.

She has signed up through Supertri’s First-Timer Programme, which supports newcomers with 12 weeks of free personalised triathlon training, live online sessions, and First-Timer expert support on race day.

Michael D’hulst, CEO of Supertri, said: “Supertri Blenheim Palace is one of the highlights of the UK triathlon calendar.

“With 50 days to go, we’re excited to welcome athletes of all levels to experience racing in such an incredible setting.

“Entries are selling fast, don’t miss your spot on race day, register now.”

Mayor Kieron Mallon held the event at Banbury Town Hall in support of the Royal British Legion’s Banbury branch and the Huntington’s Disease Association.

Themed ‘The Union,’ the evening celebrated the UK’s home nations with decor and entertainment reflecting England, Scotland, Wales and Northern Ireland.

Councillor Mallon said: “As a former Irish Guardsman whose family can go back many generations in the British Army, all in Irish regiments, the Royal British Legion was an obvious choice but some may not have heard of Huntington’s, it’s a dreadful neurodegenerative disease that is incurable and devastates whole families.

“My grandfather, Father, Aunt and Sister have all died with Huntington’s, which usually strikes when you are in your early forties.

“It’s like having both Parkinsons and Alzheimer’s at the same time but at such an early age.

“I would like to thank the town hall staff, the entertainers who gave their performances free of charge and many sponsors who gave fantastic prizes.”

Entertainment on the night included performances from a Gilbert and Sullivan singer, a soprano, Irish dancers and a pipe major who played the mayor in and out of the hall.

Councillor Mallon said: “We raised over £1,200 for these worthy causes.”

HRH The Duke of Gloucester toured the Chiltern Open Air Museum in Buckinghamshire, joined by the Lord-Lieutenant and the High Sheriff of Buckinghamshire, as part of the museum’s ongoing 50th anniversary celebrations.

During the visit, the Duke met pupils from Alder Grove Church of England Primary School taking part in an Anglo-Saxon learning day.

The Duke observed the children, who were engaged in an archaeological dig, learning to analyse and date artefacts.

HRH also explored the museum’s Victorian lambing fold and spoke with farm manager Rachael Maytum about the museum’s Oxford Down sheep and their role in the Chilterns’ farming history.

The Duke continued his tour on the Village Green, viewing a selection of historic buildings, including a 1940s prefab home, wartime Nissen huts and the newly reconstructed 1950s bandstand from Finsbury Circus.

Founded in September 1976 by members of the Historic Buildings Group of the Chiltern Society, the museum preserves threatened buildings that reflect ordinary life in the Chilterns.

Each structure is dismantled, transported and rebuilt at the site in Chalfont St Giles.

It first opened to the public in May 1981 with just four-and-a-half buildings and 95 visitors.

Since then, the museum has grown to welcome more than 50,000 visitors each year.

To celebrate its 50th anniversary, the museum is inviting visitors and volunteers to share their photos and memories via its website.