It is one of more than 100 landmarks across the British Isles which will be lit up in support of national healthcare and first aid charity, St John Ambulance.

24 June is St John’s Day, a focal point of the charity’s annual calendar of activity when the team of volunteers and staff reflect on the past 12 months and plan for future work in community.

During the past 18 months as well as providing first aid for local community and sporting events, the St John charity has responded to the changing needs of the island in delivering Covid response services, such as essential food and medicine deliveries service, the Caring Caller line and the ambulance decontamination team.

The iconic harbour fortress at the entrance to St Peter Port harbour will be illuminated as the skies darken on Thursday evening, thanks to the support of the Committee for Education Sport and Culture.

Deputy Sam Haskins, member of the committee said: "St John volunteers give up their spare time to provide first aid cover at all sorts of sporting and cultural events around the Bailiwick and the Committee for Education, Sport & Culture is very pleased to be able to demonstrate Islanders' appreciation in this way."

Nikki Harrison, Chief Executive Officer of St John Ambulance Guernsey said: “We’re immensely grateful to the Committee for Education Sport and Culture, the custodians of Castle Cornet, for agreeing to make this happen. Earlier this year St John Guernsey launched a major fundraising appeal to support our work in the island. We hope this visual reminder will inspire people to donate to the appeal and be a symbol of appreciation for our volunteers.”

St John’s Day takes place on 24 June each year, the feast day of St John the Baptist in the church calendar, reflecting the ancient origins of the organisation helping sick pilgrims in Jerusalem and the development of the modern day international first aid charity, which delivers training, treatment and humanitarian health projects to people in more than thirty countries around the world.