FLOAT
A used 1929 GBP 1 black 'Postal Union Congress' (SG 438), the St George and the dragon design by Harold Nelson - an example of the issue; the constituent prices a mint copy.

Great Britain 1929 PUC GBP 1 'Postal Union Congress'

Maker
United Kingdom
Year
1929
Rank
85 of 100

Great Britain 1929 PUC GBP 1 'Postal Union Congress'

Great Britain 1929 PUC GBP 1 'Postal Union Congress' by United Kingdom (1929) is ranked 85 in the FLOAT 100 for Stamps. It carried a price-guide value of $1,400 on 1 January 2026, which is not a sale. Britain's iconic high-value commemorative — the must-have keystone of 20th-century GB collecting.

What is it, and why is it in the FLOAT 100?

Britain's iconic high-value commemorative — the must-have keystone of 20th-century GB collecting.

SG 438, GBP 1 black (KGV), Postal Union Congress; mint; ~61,000 printed

What is the best-sourced number for it?

Figure
$1,400
Kind
Price-guide value, not a sale
Date
1 January 2026

Stanley Gibbons catalogue value GBP 1,100 for a fine unmounted-mint single (SG 438); a very-fine UM example sold at this dealer asking GBP 950. Guide-value: USD ~$1,400 is an approximate conversion of the load-bearing GBP 1,100 catalogue figure.

This is not a sale. It is what the market was asking, and no transaction is recorded behind it. Source.

How this is made

The figure
One reference price, taken from a named public source and shown with its own kind. FLOAT does not average it with anything or adjust it for time.
Realized or not
A realized price is a completed sale. A market asking price and a price-guide value are not sales, and are labeled as such wherever they appear.
Why no grade ladder
Most FLOAT 100 entries are individual objects. There is one of this, so there is no population and no spread across grades to show.
Archive
2026-08-08