Aluminium prices fell to a two-week low on Monday after data showed factory activity in top consumer China slowed further in August.

Three-month aluminium on the London Metal Exchange fell as low as $2,411 per metric ton, its weakest since Aug. 19, and as of 1039 GMT was 1.3% lower at $2,416.5.

China's manufacturing data sank to a six-month low last month, with owners struggling for orders, an official manufacturing survey showed on Saturday.

The country's real estate sector and automakers are the biggest users of aluminium.

Despite an improvement in economic data from the rest of the world, China's bearish data still carries more weight in determining metals demand, Dan Smith with Amalgamated Metal Trading said.

Aluminium had been pressured since late August by holders of long positions closing out their trades, the head of metals research of the brokerage added.

Algorithmic computer models that place buy and sell orders largely on momentum signals had flipped from buy to sell aluminium, Smith said.

In other metals, the premium of cash tin prices over the three-month contract almost doubled from Friday to $290 per metric ton.

This condition, known as backwardation, typically points to tighter supply. Tin was last down 3.4% at $31,230.

The closure of Yunnan Tin's smelter for maintenance announced last week is expected to draw down tin inventory in China, the analyst said.

Tin stocks at warehouses monitored by the Shanghai Futures Exchange stood at 10,811 tons as of last Friday.

Among other metals, three-month copper on LME was down 0.5% at $9,187.5, nickel slid 1% to $16,605, zinc moved 2% lower to $2,834 and lead rose 0.2% to 2,056.

(Reporting by Julian Luk; Editing by Jan Harvey)