An artist's impression of the completed Buchanan Galleries

Developers said the plan to double the size of Buchanan Galleries equated to an investment of more than �300m.

Two thousand jobs would be created in retail with an estimated 500 construction posts.

The venture has outline planning permission and requires approval from the Scottish Government.

Developers Land Securities and Henderson Global Investors are behind the plan.

Nick Davis, development director with Land Securities, said: "We will look to put in place an initiative to ensure that the vast majority of jobs are allocated within the Strathclyde region."

Councillor George Ryan, executive member for development and regeneration at Glasgow City Council, said: "The increased modern floor space may help to consolidate Glasgow's competitive position as the UK's biggest shopping city outside London."

The expansion will include new retail space, an atrium entrance onto Buchanan Street and new bar and restaurant facilities.