The abandoned east wing of London’s iconic Alexandra Palace entertainment venue is to be restored and reopened to the public for the first time in decades.

Three million people visit the palace every year to explore its grounds, enjoy concerts and take part in sporting events. However, it has been many years since the public have been able to access the hidden Victorian theatre and television studio located to the east of the complex.

Now, the Alexandra Park and Palace Charitable Trust – the body that owns and maintains the palace on behalf of the public – is overseeing a £27m (US$40.9m, €37.3m) renovation project to reopen the facilities as major new visitor attractions.

Architects Feilden Clegg Bradley Studios have designed the project and construction firm Willmott Dixon has been appointed to begin work imminently.

By 2018, the palace’s former BBC studios – which began broadcasting in 1936 and remained the corporation’s largest transmission station until the 1960s – will be transformed into an immersive new heritage attraction tracking the birth of TV. The studio’s interiors will be conserved to look as they did in their heyday, while access will be provided to the BBC's archives.

Meanwhile, the renovated Victorian Theatre will be transformed into a 21st century community, commercial and performance venue and banquet hall accommodating up to 1,300 people. Its original paintings, balcony and intricate stage machinery will be protected to retain the Victorian ambiance.

"When we're finished with the renovations, Alexandra Palace’s eclectic history will finally come alive, said Louise Stewart, chief executive of Alexandra Park and Palace.

“Almost half of the palace is still inaccessible to the public, but this project will help put that right. Once again it will be about Britain's innovators and pioneers, about cinema, comedy, opera and plays. It will be a true family day out.”

The Trust said Willmott Dixon was chosen as constructor for its track record in refurbishing large buildings and experience delivering projects in live environments with minimal disruption.

The firm will start work by protecting the east wing's historic features, stripping out dilapidated fittings and removing asbestos, which was used for soundproofing and fireproofing when the building was built in the early 1870s. It will also restore the Palace’s East Court entrance hall to emulate its original 1870s grandeur.

“We have extensive experience of working with listed buildings and we’ll carry out the refurbishment with full consideration of the community around Alexandra Palace and Park," said Chris Tredget, managing director of Willmott Dixon.

“Many of our team grew up enjoying Alexandra Palace, so we’re delighted to have a lead role in shaping its exciting future as north London’s most iconic building.”

The restoration project has been in development for more than two decades, but finally received a boost earlier this year when it received planning permission and key funding. The UK’s Heritage Lottery Fund has contributed nearly £19m (US$28.7m, €26.2m) for the project and a further £7m (US$10.6m, €9.6m) has been raised by the London Borough of Haringey. The Trust now needs to raise the final £1m (US$1.5m, €1.3m) to complete the project and is calling for public donations.

“This palace belongs to everyone and we will work tirelessly to make sure this money is well spent – not just conserving its amazing history, but sharing it with the world, whilst offering a contemporary cultural visitor destination," said Stewart.

"The Victorians built Alexandra Palace with the ambition to entertain, inform and educate its visitors. My job is to keep it doing just that.

"The Victorians are gone, and the BBC is gone (from the Palace), but they're not forgotten. This restoration means that it remains as true to its vision 150 years later as it was on the great day it opened.”