Derwent London is to double its rent from office space in Pentonville by building a major extension.
It intends to achieve rents of £45/sq ft and increase annual income from the £4.3 million it currently receives from BT, to £11.5 million once redevelopment has been completed.
Simon Silver, head of development said the company "can deliver an exceptional building which will be attractively priced for future occupiers".
Planning permission has been granted, which will add a further 93,000 sq ft of office space. Plans for the building include a large internal courtyard and a new public area with a mixture of restaurants and retail space.
The build has been designed by architects Alford Hall Monaghan Morris who will use three metre-high windows to bring in added light.
By combining natural light and reducing unnecessary IT resources developers cut city offices’ energy costs.