As the U.K. prepares to trigger its formal departure from the European Union, some Brits have been turning for comfort to gold.

The U.K. government is expected to trigger Article 50–the legal mechanism which will start Brexit negotiations–on Wednesday after the British voted to leave the EU last June.

The resulting political and economic uncertainty helped drive a 39% rise in U.K. gold bar hoarding in 2016, according to Ross Strachan from GFMS, part of media group Thomson Reuters.