The restaurant, which will feature views of the Houses of Parliament and Westminster Abbey, is part of a ten-year £30m total turnover deal won by Compass to provide catering and hospitality services to the Royal Institution of Chartered Surveyors (RICS).
Roux Jr's restaurant, which is due to open its doors to the public in September under Compass's Restaurant Associates banner, will feature menus created by the Le Gavroche chef-patron.
Daniel Cox, the 2008 Roux Scholarship winner, will be head chef at the venue, which is currently undergoing renovation.
Compass will also manage conference and banqueting for RICS at its grade-II listed London base, providing hospitality catering under its Roux Fine Dining brand.
Staff feeding for 400 employees in London and Coventry, as well as reception services in the capital for RICS, make up the final constituents of the deal.
Sean Tompkins, RICS chief operating officer, said: "This is an exciting opportunity for leading brands in their own rights to come together to create a unique dining and venue experience; the first fully commercial fine dining experience in parliament square."
Jason Leek, managing director of Restaurant Associates, said the RICS restaurant was particularly exciting as it was the first time the caterer had worked with Roux Jr on a commercial restaurant.
"We are sure that the restaurant, at such a remarkable location, will be very successful," he said.
The tender was managed by foodservice consultant Peter Pitham of Catering Consultancy Bureau who described it as an interesting challenge as it combined three disciplines: fine-dining, conference and banqueting and staff feeding.
Services at RICS were previously provided by Sodexo's Directors Table.
By Chris Druce
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