Central banks have all but stopped lending gold to commercial and investment banks and other participants in the precious metals market, in a move that yesterday sent the cost of borrowing bullion for one-month to more than twenty times its usual level.

The one-month gold lease rate rocketed to 2.649 per cent, its highest level since May 2001 and significantly above its five-year average of 0.12 per cent, according to data from the London Bullion Market Association.