The yield on 10-year UK government bonds was indicated at a new low on Friday, according to pricing data from bond platform Tradeweb, as investors rushed to the safety of government debt after Britain's vote to leave the European Union.

Tradeweb usually starts offering quotes at 0800 London time but opened at 0400 London time on what turned out to be a historic day.

Traders said there has been very little - if any - actual trading and the prices on the screens were largely indicative. But Citi's rate strategists lowered their 10-year gilt yield forecast to 0.9 percent on Friday.

German 10-year yields were indicated at a fresh all-time low of -0.10 percent, according to Tradeweb quotes, and U.S. Treasury yields tumbled to a four-year low of 1.406 percent.