Sharecast - The S&P Global/ CIPS flash services business activity index dipped to 49.2 from 49.3 in September, falling for the third month in a row. Economists were expecting the reading to be unchanged on the month.
The manufacturing output index ticked up to 45.3 in October from 44.6 a month earlier.
A reading above 50.0 indicates expansion, while a reading below signals expansion.
The composite output index - which measures activity in the manufacturing and services sectors - nudged up to 48.6 from 48.5, but remained below 50.0 for the third month running. Analysts were expecting an unchanged reading.
Chris Williamson, chief business economist at S&P Global Market Intelligence, said: "The UK economy continued to skirt with recession in October, as the increased cost of living, higher interest rates and falling exports were widely blamed on a third month of falling output.
"The overall pace of decline remains only modest, signalling a mere 0.1% quarterly rate of GDP decline, but gloom about the outlook has intensified in the uncertain economic climate, boding ill for output in the coming months. A recession, albeit only mild at present, cannot be ruled out."