The British Bankers Association (BBA) reported the big high street banking groups increased lending to non-financial firms by £2.5 billion in September net of repayments after taking billions of pounds of credit out of the economy in previous months.
The increase in net lending was only the third in the past 11 months and was the largest since January 2009.
Banks reduced lending by a monthly average of £1.4bn in the preceding six months.
The increase in lending may indicate official efforts to breathe more life into credit markets through the Funding for Lending scheme are paying off.
The scheme was introduced following repeated claims that risk averse banks were starving small and medium sized enterprises of affordable credit.
The BBA said lending to SMEs was stable in September.
Howard Archer, chief UK economist at IHS Global Insight, said the size of the increase in lending may show banks are becoming more prepared to lend to businesses given the improved economic outlook and that companies are starting to significantly step up their borrowing.
Colin Borland, head of external affairs at the Federation of Small Businesses in Scotland, said net lending rise seemed to reflect a strengthening of businesses' investment intentions.
Some 30% of the federation's members in Scotland plan to increase their capital investment in the months ahead.
But, Mr Borland added: "About half of our members are still reporting the availability of credit as poor and a third say it is unaffordable."
The Centre for Economics and Business Research noted minutes of this month's Bank of England's interest rate setting committee referred to rising consumer and business confidence implying growth will strengthen. But members of the Monetary Policy Committee unanimously voted to keep interest rates at the record low rate of 0.5% and to hold the bank's quantitative easing facility at £375bn.
The CEBR expects an interest rate rise next year but is worried about the sustainability of the long-term recovery. IHS Global Insight does not expect a rate rise before the latter months of 2015.
The number of mortgages approved for home purchases increased to the highest level since December 2009 in September, to 42,990, from 38,834 in August.