The refurbishment plan has been launched as part of plans to celebrate the venue’s 150 anniversary in September.

Colston Hall’s remodelling and upgrading has been designed by architects Levitt Bernstein.

It will see the capacity of the main concert hall increased and major changes to the stage, making it more flexible and able to accommodate larger bands and orchestras and more production equipment.

Colston Hall’s second venue, The Lantern, will also be redeveloped into a versatile performance venue with flexible seating technology.

The venue’s historic cellars will be used again for the first time in 100 years, turned into educational workshop spaces, a hub for performing arts business enterprises and a new performance area.

The Lantern hall will also be refurbished

Colston Hall’s cellars will be opened up for the first time

Colston Hall’s frontage will also be restored and a new restaurant will be built where the venue’s old ticket office currently sits.

A formal planning application is due to be submitted later this year.

It marks the second phase of improvements in recent years. The first phase involved the construction of the £20m foyer space, which opened in 2009.

The rest of the building has not been refurbished for 60 years, making it the only major concert hall in the UK not to have been redeveloped in recent times.

Under the plan, Colston Hall’s main hall and The Lantern will be closed from early summer 2018 to Easter 2020 to allow for the construction works.

Louise Mitchell, chief executive of Bristol Music Trust: “The Hall hasn’t been updated since the 1950’s, so it’s long overdue a refurbishment that will give Bristol and the West Country a world class venue to be proud of.

“Today, we invite the public to view our plans for the Hall that will transform it into a performance centre fit for the 21st century and secure its place as a leading national arts centre for the next 150 years.”

The Trust is working with a range of funders, including Arts Council England and Heritage Lottery to secure project finance.