Taken from the top of BT Tower, the 320 gigapixel image comprises of 48,000 individual frames collated into a single panorama, which can be viewed here.
You can explore the image through 360 degrees, and BT has also hidden its old mascot Buzby within the photo.
This is the first time that an image of this size has ever been attempted. If printed at normal photographic resolution, the panorama would be 98 meters across and 24 meters tall, almost as big as Buckingham Palace.
The last record attempt for a London panorama was 80 gigapixels, taken from Centrepoint in 2010.
The image is the final part of the celebration of London 2012, with the Olympics last year claimed to be the first "digital games". It is also part of the 360Cities project.
"The BT Tower is such an iconic London landmark, and became a focus for the capital's celebrations in 2012, what better way to capture that remarkable year than with a full panoramic photograph taken from its roof," said BT's Suzi Williams.
"This isn't just a world record for the BT Tower, it's for London and the people who live, work in or visit the capital. Take a look, and share your favourite London places and landmarks."
Four Canon EOS 7D cameras with EF 400mm f/2.8L IS II USM lenses and Extender EF 2x III teleconverters were used to take the images. They were fitted with robotic panorama heads and positioned on the 29th floor of the tower.
The raw images captured were processed over a few weeks at the Fujitsu Technology Solutions' Celsius R920 workstation, requiring 256GB of RAM and 16 cores at 3.1GHz.
The resulting online interactive version of the photo is presented in multi-layered, tiled resolution that allows users to zoom in to view even the closest details. .