London CNN Business  — 

UK Finance Minister Kwasi Kwarteng will try to avoid spooking investors a second time when he publishes details of plans to tackle ballooning government debt and kickstart economic growth on Halloween.

Kwarteng announced the Oct. 31 date in a letter to the Treasury on Monday, pulling his midterm budget forward by more than three weeks in an attempt to reassure rattled markets and rebellious party colleagues. He also confirmed that the Office for Budget Responsibility (OBR), the independent fiscal watchdog, will publish its assessment of the budget on the same day.

Investors have been awaiting clarity on a revised date for the budget, which was initially set for November 23. It was widely expected to be brought forward after Kwarteng’s “mini” budget on Sept. 23 crashed the pound and sent shockwaves through financial markets with its promise of £45 billion ($49.8 billion) of unfunded tax cuts.

The reaction to the “growth plan” crafted by Kwarteng and Prime Minister Liz Truss was swift and brutal. Bond prices collapsed, sending borrowing costs soaring, sparking mayhem in the mortgage market and pushing pension funds to the brink of insolvency. The Bank of England was forced to stage an emergency intervention, pledging to buy up to £65 billion ($72 billion) of government debt to avert a market meltdown.

Standard & Poor’s and Fitch, meanwhile, downgraded the outlooks on their UK government credit ratings from “stable” to “negative” on concerns over the growing debt burden.

The pound has recovered all of its losses but UK government bond yields remain higher than they were before the crash.

In a sign that markets remain fragile, the Bank of England said Monday that it will double the daily limit on bond purchases to £10 billion ($11 billion) throughout this week and extend support for banks beyond October 14, when its emergency bond-buying program ends.

The revised date of Kwarteng’s budget will give the Bank of England time to digest its effect on markets before it meets on Nov. 3 to set interest rates. The outlook for the UK economy has darkened substantially since the bank’s last meeting just over two weeks ago, which took place less than 24 hours before Kwarteng’s disastrous speech.

With inflation near 10% in Britain, bond yields elevated and a Federal Reserve unrelenting in its mission to tame inflation, the bank may need to hike rates much more aggressively when it meets again.

Winning investors back

A lot is riding on the Oct 31. budget and the OBR’s analysis of its impact on growth and government debt.

“For the chancellor to get the markets back on side he would need to show that the numbers add up and that the plans are credible,” Paul Dales, chief UK economist at Capital Economics told CNN Business.

Kwarteng has already been forced into an embarrassing retreat on his proposal to abolish the top rate of personal income tax — by far the most controversial element of sweeping tax cuts that included a reduction in duties on house purchases and the cancellation of a planned hike in business taxes.

But the reversal on tax cuts for the rich will save the government only around £2 billion ($2.2 billion), leaving investors worried that debt will spiral in order to fund the rest.

The government will need to show how it plans to “fill the fiscal hole” its policies have created, according to Dales.

— Mark Thompson and Anna Cooban contributed to this report.