The yield on the 1.625 percent 2028 gilt, the new 10-year benchmark, touched 1.525 percent at 1413 GMT, its highest level since Aug. 2, the day the Bank of England raised interest rates to a new post-financial crisis high.
The rise came shortly after Bloomberg reported that Britain is helping Brussels solve issues around the Irish border, a sticking point in Brexit talks. A spokesman for British Prime Minister Theresa May subsequently declined to comment on the report's accuracy.
As of 1515 GMT the 10-year gilt yield stood at 1.505 percent, up 2 basis points on the day.
The 30-year gilt yield touched its highest level since mid-June at 1.874 percent.
Gilts showed little reaction to the Bank of England's decision to hold interest rates at 0.75 percent earlier in the day, which had been widely expected.
Instead, they moved largely in step with German Bund yields, which also hit six-year highs as the European Central Bank sounded upbeat on the inflation outlook.
The yield spread between 10-year British and German government bonds stood at 108 basis points, little changed on the day.