The "Sesame" lift will allow wheelchair users to gain access directly from the Westminster building's front entrance.
In order to make room for Sesame, two flights of stone steps at the building's entrance were cut out, and two lifts were installed.
The steps were then put back into position, but they retract at a simple touch of a button. ICE past president Quentin Leiper, said: "We are delighted to have a state-of-the-art wheelchair access lift located at ICE's Westminster headquarters. I believe the Sesame lift configuration has never been used like this before, and I am sure that others will now follow our lead."
Aptly, fitting the lift was an engineering challenge, balancing the absolute need with consideration for the architectural heritage of the building. Work began in July and completed in September.
While the ICE was not legally compelled to fit the access lift, it decided that it was an overwhelming benefit to wheelchair users.
The lift has a secondary benefit for One Great George Street's popularity as a quality commercial venue in central London.
The ICE has also installed a wheelchair ramp to the Telford Theatre stage, a new disabled toilet, new improved signage, new handrails and new stair treads to over the summer.