UK long-term borrowing costs have risen to 6% for the first time in nearly three decades, as entrenched inflation and a growing government debt burden fuel concerns that are driving global bond yields higher.

The yield on 30-year UK government bonds, known as gilts, climbed 6 basis points to 6.01%, marking the highest level since March 1998. The last time a Group of Seven nation's government bond of the same maturity touched this level was during the 2012 European debt crisis, when Italian bonds were selling off. On Thursday, the US 10-year Treasury yield also rose to its highest level since 2002.

Gilts came under pressure as rising oil prices heightened the risk that the Bank of England and other developed-market central banks may need to tighten policy significantly to curb inflation. This further intensifies the strain on UK public finances, with Prime Minister Andy Burnham and Chancellor John Healey preparing to unveil their first budget on October 28.

"Rising oil prices, stronger European inflation data, and the ongoing sell-off in global duration assets" are all weighing on sentiment toward UK gilts, said Evelyne Gomez-Liechti, a multi-asset strategist at Mizuho International.

The swaps market has now priced in four Bank of England rate hikes by the end of next year and sees a 70% chance of a fifth. Government data shows that UK debt interest payments are the second-largest spending item after healthcare, and the Office for Budget Responsibility expects this figure to continue rising in the coming years.

In other markets, the US 10-year Treasury yield rose 4 basis points to 5.33%. The German 10-year bund yield climbed 5 basis points to 3.64%, while the French 10-year government bond yield rose 9 basis points to 4.95%. This widened the yield premium investors demand to hold French debt over German bunds to more than 130 basis points.