Customs and Excise, Crown Seal, Image by StuE, Found by Goretex.
Found in England, 15mm, 4.2g.
On one side is the British crown and on the other the incomplete phrase CUSTOMS (curved around the top) AND (straight across the middle and obscured by two heavy indentations) EXCISE (straight across the bottom).
A U.K. customs & excise seal.
The Tudor crown indicates it is from a date before 1953 - Wikipedia.