It means that four office schemes were approved in July as investors sought to exploit surging demand for top-class energy-efficient offices with outdoor spaces for staff.

The rise in carve-and-construct projects is also being driven by the City of London Corporation’s retrofit-first planning policy.

The biggest of the latest project to be approved is a £250m scheme to revamp and expand Deutsche Bank’s former headquarters at 75 London Wall, known as Winchester House.

While a contract is still to be awarded, Multiplex is tipped to take the big job which will see a large uplift in new office space, while retaining 90% of the existing building.

Three new floors will be added to the London Wall building

The project will see three extra floors aadded to the building to create 320,000 sq ft of space.

The client team includes architect Orms, M&E consultant Hoare Lea, with structural engineering provided by London Structures Lab.

The other office upgrade at 1 Basinghall Avenue near Moorgate Tube station is the former headquarters for Standard Chartered Bank.

Former investment bank HQ at 1 Basinghall Avenue will be transformed

Overbury is understood to be in line for the retrofit which will see the 10-storey building upgraded in a 69-month project.

Designed by Stiff & Trevillion Architects, the building will require extra massing to support a new rooftop terrace, with an extensive M&E refit and new glazing.

The ground floor entrance lobby will be remodelled to enable space for a new café, or restaurant

Chair of the City of London Corporation’s Planning and Transportation Committee, Shravan Joshi, said: “Attention is always drawn towards the latest large new office developments in the City, but when it comes to retrofitting, the City is leading the way on both policy and delivery, accounting for around half of all major retrofit applications across Greater London.

It signals once more to investors, that the Square Mile is open for sustainable business.

The other two project approve this month were St Magnus House on the Thames north riverside path in front of the Walkie Talkie building.

Architect Buckley Gray Yeoman designed the St Magnus project

Developer Pegasi’s plan for the Lower Thames Street building includes creating more green terraces as well as improving the building’s energy performance and public realm.

Also in the heart of the Square Mile, developer Deka Immobilien gained planning to refurbish 1 Old Jewry, adding a new top floor level with outdoor terraces.

Refurbishment is anticipated to start later this year on 1 Old Jewry building

Designed by architect Sheppard Robson,  the proposed refurbishment will comprise 70,000 sq ft of Grade A office accommodation arranged over first to ninth floors and 5,000 sq ft of remodelled retail accommodation.