Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 146,747 pages of information and 232,260 images on early companies, their products and the people who designed and built them.
1910 The General Post Office built a new power station near Blackfriars Bridge to supply three-phase current at 6600 volts and 50 Hz to sub-stations with 2.5MW generating capacity and room for extension. It would supply the power requirements of the King Edward's Building and to replace generating plant at St Martin's-le-Grand; much of these power requirements were in connection with the pneumatic tube system which radiated from St Martin's. 
The Post Office's Central London Station was in Upper Ground Street, near Old Barge House Street, Southwark. It was closed around 1926. It was noted in the advert for sale that, although the property occupied higher ground, there was not an embankment on the south side of the Thames at this point.
c1927 The site was acquired by the Liebig Extract of Meat Co for conversion into a cold store.
1928-9 The building was largely rebuilt to an Art Deco design by company architect Albert Moore. Much of the original power station was demolished, but the river-facing facade was retained and extended.