Best architectural staircase: Hayward gallery in London or Bristol block of flats?

How beautifully cool is this external staircase!  One of two, attached to Brandon House on Jacob's Wells Road in Bristol, I think it is 1950s but have not managed to find out for sure yet.  Apparently, so I am told, these external stair cases are considered such an architectural icon that they have gained listed status.  And I mean they have gained listed status, not the block of flats it serves, oh no, they can be razed without causing English heritage to put down their tea cups or raise a tobacco-scented eyebrow in interest.  As long as those elegant geometric lines remain standing tall just metres from Brunel's SS Great Britain then no crime has been committed and may the earl grey continue to flow beneath the most cultured of moustaches.

But oh what's this?  Do I spy those very same spiralling shapes adorning a slightly less mighty erection beside London's Hayward Gallery in the south bank centre?  Indeed I do!  And some comedian has painted them a custard yellow to match the visually uninspiring attempt at sign-writing that came from someone who feels confident they can elect themselves to be choreographing me yet seemingly unfazed by their own offensive use of unnecessary hyphenation.  Oh dear, our nation's capital is in a funny mood.

So I feel a quest coming on.  Or rather, a new obsession.  Along with collecting photographs of stub-footed pigeons I fear I may now begin also seeking out architectural examples of these wonderful staircases.  If you know anything about the architect or dates these were being built please do comment now.  I would be ever-so appreciative.