This is looking more and more like an old fashioned bank run:
Bank of England suffers exodus of gold bullion
https://www.telegraph.co.uk/business/2025/02/07/bank-of-england-suffers-exodus-gold-bullion/
Mind you the BofE has form on keeping other countries gold:
Why is Venezuela’s gold still frozen in the Bank of England?
I think that the threat of tariffs is something of a red herring