Portcullis House is an office building in Westminster, London, UK, that was commissioned in 1992 and officially opened by Her Majesty the Queen in February 2001. The building provides offices for 213 members of parliament of the United Kingdom and their teams.

Portcullis House was designed by Michael Hopkins and Partners, with structural engineering completed by Ove Arup & Partners.

The diamond patterns formed by the timber elements are all cross braced by Sta-Lok stainless steel rods. These are single rods in the plane of the parabola while running the other way, pairs of inclined rods support a central flying strut which carries the glazing. These pairs of rods are able to resist both positive and negative loads.

Sta-Lok supplied 6264 individual pieces involved in the construction of the atrium roof. The timber elements are joined by stainless steel nodes to which they attach using an anti-slip type connection.