Post Office Tunnels: Reiss HQ, 9-12 Barrett Street


This project involved the construction of a seven storey new build retail and office block on a site close to Oxford Street in Central London.


  • Project Cost £25 million
  • Architect Squire & Partners
  • Images Fluid / Squire & Partners

The site was occupied by a series of Victorian steel framed buildings that were linked together. The Picton Place façade is a Victorian façade. However, the Barrett Street façade appears to have been replaced in the 1950’s.

The following main elements of work were carried out: 

  1. Installation of façade retention scheme on Picton Place (temporary works/ propping supported on minipiles).
  2. Demolition of existing steel frame buildings and removal of  the existing redundant foundations.
  1. Construction of new reinforced concrete framed building comprising basement, ground, 1st, 2nd, 3rd, 4th, 5th, 6th and roof with roof top plant areas.
    6th and roof with roof top plant areas.

One of the post office tunnel shafts was located next to the site and before any construction work could begin the structural design had to be agreed with the engineer’s responsible for the Post Office Tunnel.


  • Possibility of damage or collapse of shaft.

Design Procedures

  • We contacted the post office at an early stage in the project before any design work had commenced and agreed methods of construction that would be acceptable close to the shaft.
  • We carried out a detailed site investigation and we also carried out a condition survey in conjunction with the Post Office prior to any work starting.
  • Based on our drawings, calculations and meetings the feasibility of the proposed works was established and agreed with the Post Office.