The London International Stamp Exhibition was held from 14-26 May 1923 in the Royal Horticultural Hall, London.
One of the key exhibits was the collection of Victoria Half-lengths formed by Charles Lathrop Pack along with his Diligencias.
The roof of the hall was shaded to protect the numerous exhibits from the Sun and whitewash was used.
[1] International Stamp Exhibition, Royal Horticultural Hall, London, May 14-26, 1923.
Junior Philatelic Society, London, 1923.