UK bond prices rose again on Friday following a speech by Prime Minister Liz Truss, hours after she fired her finance minister, sparking more concerns about political instability among investors.

The yield on 10-year bonds ended the week on 4.39 percent, close to the 4.64 percent realized on Thursday, its highest level since 2008, while the rate on 30-year debt climbed to 4.77 percent.

Truss also on Friday reversed plans to cancel an increase in the corporate tax rate.

That policy was a major part of her "mini-budget", the announcement of which triggered uncertainty in the markets in late September.

Truss insisted during a press conference following Kwasi Kwarteng's sacking that she had acted "decisively" to bring about "economic stability".

But traders didn't appear to be reassured, with the pound sinking and bond rates climbing.

"Unfortunately for Truss, her swift ability to spook markets with a swathe of unfunded spending plans is now being followed by yet another rise in yields as markets wonder whether we could soon see another push to replace her," said Joshua Mahony, an analyst at IG.

The bond market is also digesting the end of the Bank of England's (BoE) long-term bond-buying program, initiated a few days after Kwarteng's budget announcements to prevent a vicious circle of forced sales by pension funds.

The Bank bought 19.25 billion pounds (about $21.50 billion) of bonds.

While 30-year rates have fallen since the program began on September 28, they are dangerously close to the 5.14 percent peak reached on that day.

The BoE governor earlier in the week pledged that the buyback program would not be extended.

The British business community welcomed Truss's intervention, apparently settling for higher taxes in exchange for more stable markets.

"The instability of recent weeks has paused investment and hit livelihoods, so it was important today that the government responded to those market concerns," the CBI lobby group said in a statement.

"In the weeks to come, government plans will need to continue to restore fiscal credibility to give markets and business confidence to invest," it added.