London's National Theatre (NT) has submitted plans for a major £70m overhaul of the South Bank venue in a bid to transform its facilities and "open up" to more people.

The theatre has been working alongside architects Haworth Tompkins over the last two years to draw up development proposals as part of its NT Future scheme, which could get underway in late 2011. Lambeth Council will now decide the fate of the plans, which include a new education and participation centre - Discover - to enable a further 50,000 people a year to engage in onsite training activities.

The Cottesloe Theatre and its foyer will be transformed to incorporate a number of education spaces, while its auditorium will benefit from work to expand capacity, improve access and enhance technical facilities. NT Future is set to open up the Grade II*-listed building with a high-level walkway through workshop and backstage areas, linking the Cottesloe to the venue's main foyers.

A new production building to the south of the NT is proposed, while the theatre's riverside entrance will be enhanced. Goods facilities are set to be turned into a café bar and the bookshop will be relocated. Plans also include the refurbishment of external areas to provide green space and gardens, while the NT aims to reduce energy consumption and replace ageing technical infrastructure.

A NT spokesperson said that funding would be sourced from a private and statutory bodies, while it is anticipated that part of the scheme will be complete in time for the venue's 50th anniversary in 2013. NT director Sir Nicholas Hytner said: "We're proud of our building and proud of the work we bring to our audiences. But if that work is to keep developing, then our building has to develop too.

"We want to give our audiences a greater understanding of the plays they see and encourage the public to participate in the process of making theatre. When NT Future is realised we want to say - as the NT did when it first opened - the New National Theatre is Yours."