Dudley Zoological Gardens (DZG) is a step closer to embarking on a £1.5m redevelopment of its four iconic Tecton structures after securing a first-round funding pass from the Heritage lottery Fund (HLF).

HLF awarded DZG development funding of just over £123,000, giving the zoo up to two years to submit more detailed plans and apply for a full HLF grant of £970,000 towards the project.

The attraction contains the world's largest single collection of Tecton buildings, named after the modernist architects chosen to design the Zoo in the 1930s and led by Russian-born Berthold Lubetkin.

The scheme, scheduled to begin in 2012, will see the repair, renovation and new interpretation of four of the Tecton structures - Bear Ravine, Front Entrance, Safari Shop and Kiosk One - plus the refurbishment of the region's only chairlift which next year celebrates its 50th anniversary.

The Tecton structures were designed and constructed between 1935 and 1937 using reinforced concrete - a pioneering system at the time.

The funding will also support a signage and education project for the programme.