The refurbished venue has invested £3 million on restoring historic features as well as adding 25 bedrooms. It has taken more than three years to complete the project and will offer groups the chance to hire out the venue on an exclusive basis.
Clevedon Hall managing director John McCarthy said: "Clevedon Hall is a stunning 150-year-old building that has a wealth of history and has been used for many purposes, including an all girls school.
"It’s great that we are finally able to fulfill the building's full potential as an outstanding luxury exclusive conference venue. We’re absolutely thrilled with the results – the refurbishments look fantastic."
He continued: "It’s also fantastic that we can now offer guests the opportunity to not only hold their private event but also stay at the mansion."
Clevedon Hall's main event space can accommodate 150 guests seated.
Thursday's official opening was attended by VIPs, business professionals and local residents.