The design is a two-storey building in a trapezoidal layout

The building will be built on the site of the former Great Western Railway works and employ about 430 staff, currently split between four sites.

Offices in Cirencester, Melksham and Westbury are due to close while the organisation's base in central London will be replaced with a smaller office.

The Trust said all staff had been offered the opportunity to relocate to the new headquarters.

Summer 2005

Architects have designed a two-storey building in a "trapezoidal"layout.

Jo Wright, from architects Feilden Clegg Bradley, said: "We have tried to show that it is possible to meet institutional funding requirements and deliver a sustainable building which will provide a long term home for the Trust."

The plans have been submitted to the borough council and the Trust hopes - if plans are approved - that it can move in by summer 2005.

The Great Western Railway works closed in 1986 after 143 years of operation.