I did find this:
In the United States, beverages containing less than 0.5% alcohol by volume (ABV) were legally called non-alcoholic, according to the now-defunct Volstead Act. Because of its very low alcohol content, non-alcoholic beer may be legally sold to minors in many American states.
Low-alcohol beer - Wikipedia
In the United Kingdom, the following definitions apply by law (correct as of May 2007):
No alcohol or alcohol-free: not more than 0.05% ABV
Dealcoholised: over 0.05% but less than 0.5% ABV
Low-alcohol: not more than 1.2% ABVhttps://en.wikipedia.org/wiki/Low-alcohol_beer