The British Museum has revealed it is progressing on schedule for the opening of its new £135m exhibition space, due to open in March 2014.

Construction on the World Conservation and Exhibitions Centre (WCEC) began in autumn 2011 in the north-west corner of the museum's central London estate.

The redevelopment project is one of the largest in the museum's 260-year history and will include a new public exhibition gallery, state-of-the-art laboratories and studios, stores for the collection and a centralised object handling facility.

Four fifths of the total cost has been raised, with £25m coming from Sainsbury Family Charitable Trusts, The Linbury Trust and Monument Trust, one of the largest gifts to the arts in the UK in recent decades.

The Heritage Lottery Fund has committed a further £10m and the Department for Culture, Media and Sport £22.5m.

In total the Rogers Stirk Harbour + Partners space covers 18,000sq m (193,750sq ft) and five pavilions, one of which is submerged below ground.

Construction will finish in autumn this year before furniture and equipment are moved into the building.

A major exhibition on the Vikings, including the remains of a 37m (121ft) ship, will be held in conjunction with the opening of the new wing.