Billions of pounds of emergency cash are expected to be pumped into the UK economy.
The Bank of England's monetary policy committee is widely predicted to boost its quantitative easing programme by a further £50 billion ($97.15 billion) to £375 billion at its latest monthly meeting overnight.
Figures this week showed the economy worsened last month, after the construction and manufacturing sectors contracted and the services sector suffered its worst performance in eight months.
Economists said the figures suggested the economy continued to shrink or at best was flat in the second quarter, making it more likely the bank would act.
Nida Ali, economic adviser to the Ernst & Young ITEM Club, said the surveys released this week "have disappointed" and "strongly suggest" the bank would authorise extra quantitative easing, "probably to the tune of £50 billion".