Thank you, Anne, Sue and Frank!
What does UGB stand for? United Glass Bottle manufacturing co?

To cut the story short: this item originates from Shanghai, China, where my parents-in-law lived during the Thirties and Fourties. They returned to Europe in 1950 resp. 1951.
The silver pattern is in fact very Chinese, showing dragons, clouds etc.
My fil also gave work to the orphanage in Shanghai by ordering huge embroideries. Maybe he himself liked this bottle and has had it decorated this way to give it a better look - I know he liked Whisky

Unfortunately he passed away in 1982 already and I cannot ask...

My mil wouldn't even recognize it today, very sad about her.
The silver is stamped:
SILVER and ZEESUN.. (may read 'Co')