Britain's manufacturers have just posted their highest reading in five months, and for a FTSE 100 already bracing for Thursday's Bank of England decision, that is not entirely good news.

Good news on the factory floor, mixed news for markets

UK factories had a better October than many expected. The UK Manufacturing purchasing managers' index rose to 52.8, up from 51.9 in September, the highest reading in five months. A figure above 50 signals expansion, so the survey points to a sector that is not just growing but picking up speed.

In normal times, that would be a straightforward boost for equities. These are not normal times. The survey arrived as the Bank of England prepares to announce its rate decision on Thursday 5 November, with Bank Rate at 3.75% and a quarter-point rise to 4% widely expected. Markets price that move at around 95%.

The awkward detail is in the price data. The survey's compilers said the combination of resilience and surging input prices "will further shorten the odds of Interest Rate hikes". For policymakers worried about inflation, a busy factory sector paying more for its materials is exactly the kind of signal that argues against holding fire.

That is the tension now running through the FTSE 100. Firmer activity supports earnings, but it also strengthens the case for tighter policy. Investors have to weigh one against the other, and the PMI tipped the scales towards the hawks.

Where the index stood when the data landed

The FTSE 100 shrugged off any immediate worry on Monday 2 November. The index closed at 10,761.33, up 31.55 points or 0.3%, its fourth straight daily gain. It had been essentially flat at midday, sitting at 10,724.58 at 12:15pm GMT, before recovering through the afternoon.

The bigger story on the day was oil. Brent Crude dropped to $105.09 a barrel at the London close, from $117.61 on Friday, on reports that Washington and Tehran were considering renewed negotiations. Energy stocks fell hard: Ithaca Energy (LSE:ITH) lost 5.94%, BP (LSE:BP.) fell 4.37% and Shell (LSE:SHEL) slipped 2.86%. The FTSE 350 energy sector shed 3.3%.

Meanwhile, the industrial and consumer end of the market rallied. Weir Group (LSE:WEIR), the engineering business, rose 4.23%. No company-specific news was reported for that move. Reports linked the broad advance in consumer, travel and construction stocks to lower oil prices, which ease transport costs. Construction and materials climbed 2.8%, and travel and leisure 2.7%.

Why input prices matter more than output

A PMI reading is a snapshot of sentiment among purchasing managers, but its price components are watched closely by central banks. When firms report that their own costs are rising quickly, the worry is that those costs will eventually be passed on to customers, keeping Inflation elevated.

The context makes that worry sharper. UK inflation rose faster than expected in September, and one of the watch points market watchers have flagged for Thursday is whether the Bank's new forecasts show inflation topping 4% early next year. A solid, cost-pressured manufacturing sector makes that scenario harder to dismiss.

Monday's oil slump adds a twist. Lower crude, if sustained, could eventually ease some of the input cost pressure that factories are reporting. But one day's fall does not rewrite a month of survey data, and Brent was still above $100 a barrel. Whether the drop endures depends heavily on the progress of any US–Iran talks. Iranian Foreign Ministry spokesman Esmaeil Baghaei signalled that Tehran now regards the next move as Washington's.

Bond markets add another layer. UK 10-year gilt yields reached 5.44% earlier in October, a 19-year high, before late-October reports placed them below 5.3%. Any data that strengthens the case for more hikes could put pressure back on gilts, and higher borrowing costs tend to weigh on rate-sensitive parts of the FTSE 100.

Within the MPC, the hawkish camp is established. Megan Greene, Huw Pill and Catherine Mann voted for a hike at the June, July and September meetings, while Clare Lombardelli has been described as a swing vote. Economists expect a 7–2 vote this week and see a February follow-up as more likely than not. Data like October's PMI make it easier for that February scenario to gain traction.

Illustration: suppose a hypothetical manufacturer has £10m of annual input costs and those costs rise 5%. Its bill climbs by £500,000 to £10.5m. If it passes on 60% of that increase, customers absorb £300,000 and the company carries the remaining £200,000. The numbers are invented, but they show how input price pressure can flow into both consumer prices and corporate margins at the same time.

Key dates to watch

  • Wednesday 4 November: Weir Q3 interim management statement
  • Wednesday 4 November: Eurozone inflation figures, expected to rise to 3.9%
  • Thursday 5 November: Bank of England rate decision, with Bank Rate at 3.75% and a rise to 4% widely expected
  • Thursday 5 November: Croda Q3 update
  • Friday 6 November: US October payrolls
  • Thursday 12 November: UK GDP first quarterly estimate for July to September, 7:00am

The bottom line

October's factory survey is a reminder that in the current cycle, solid data can be a double-edged sword for the FTSE 100. Growth in output is welcome for corporate earnings, but surging input costs feed straight into the Bank of England's inflation calculus. With a rise to 4% already priced, the PMI matters less for Thursday's decision than for what follows it. Investors will be watching whether the Bank's forecasts and Andrew Bailey's tone treat this resilience as a reason to keep tightening into the new year, or as a pressure that lower oil may soon relieve.

Weir's update on Wednesday offers a timely company-level read on industrial Demand ahead of the decision. Engineering and industrial names rallied on Monday without specific news, so any trading commentary will be scrutinised for signs of whether the resilience in the PMI is showing up in real orders and revenue. Croda's Thursday update, landing on the same morning as the Bank, will give another angle on how manufacturers are coping with costs.