THE new development is expected to fill one of the last remaining gap sites in the Capital's booming financial district.

It is thought more than 1500 people will be working in the eight-storey 191,000 sq ft office complex once it is fully let.

A striking new atrium building will act as an entrance for both the existing EICC and the extension. Several retail units will be provided on the ground floor of the office complex, which will be set back from a landscaped public area.

However it is the underground extension, which will be able to host 1600-seater events, which is seen as key to Edinburgh's ability to compete with other cities around the world to host major conferences and events.

The underground area would allow event organisers to transform 17,000sq ft of flat-floor exhibition or banqueting space into a variety of tiered seating arrangements, using a computer-controlled moving floor.