The practice released images of the tower this week to coincide with the fifth birthday of its high-profile London Eye.
The plans for the needle-like landmark - named the I-360 because of the panoramic views it offers paying customers - feature a slow-moving viewing capsule that will be raised and lowered. The total trip will take 30 minutes.
According to the architect, the spire will be cheap to construct compared with an observation wheel. It will also have low operating costs and will be suitable for a number of locations.
The practice's aim is for the spire to attract up to one million visitors a year.
In 1994 Marks Barfield founded the London Eye Company and raised the capital necessary to build the wheel. Since opening in 2000, the London Eye has become the most popular pay-for attraction in the UK.