The Wolfson Foundation awarded £5m to the Tate Modern on 12^th April towards a £215m development that will create a new building to increase the size of the gallery by 60%.

Over £172m, 80% of the total cost, has now been raised for the project. This includes £50m from government and £7m from the Greater London Authority with the remaining £115m from individuals, charitable trusts and foundations. Donors include the Blavatnik Family Foundation, the Dr Mortimer and Theresa Sackler Foundation, and Elisabeth Murdoch.

The building will be completed by 2016 at the latest, Tate Modern said. It will provide more space for contemporary art and enable Tate to explore new areas of contemporary visual culture involving photography, film, video and performance, enriching its current programme for a broader audience. Last year Tate Modern attracted 5.3m visitors, the highest ever figure in its history, making it the second most popular tourist attraction inBritain.

Philanthropist and art collector Janet Wolfson de Botton, chairman of the Wolfson Foundation said: “We are delighted to be contributing to this exciting project at an organisation which has done more than any other to bring contemporary art to a mass audience. Tate Modern has been a remarkable success story since its opening in 2000.”

In a statement Tate Modern said the development will be Britain’s most important new building for culture since the creation of the British Library in 1998.

Nicholas Serota, Director, Tate said: “We are hugely grateful to the Wolfson Foundation, whose generous gift of £5 million will make a real difference to the transformation of Tate Modern.”

He added: “It coincides with a landmark in the project’s development, as the ten-storey concrete core is completed and visitors to Bankside can truly begin to see the new building taking shape.”

The new building’s two central concrete cores are now complete and will house the lifts, stairs and services. The higher, at ten storeys, reaches the full height of the new building, standing at 64 metres. The cores are being surrounded by a lattice of columns, which will continue to rise throughout the year to form the perimeter of the new building.

Alex Beard, deputy director of Tate for the past decade and credited as an important part of the success of Tate Modern, was last month announced as successor to Tony Hall as chief executive of the Royal Opera House. He will take up the post in time for the 2013 season that begins in September.