Copper hit a three-week high in London on Monday after reports showed growth in manufacturing data from China, the world’s No. 1 consumer of the red metal.

According to two different surveys, China’s manufacturing sector improved last month, which it is considered by many a sign of recovery in the world's second biggest economy.

The private HSBC purchasing managers' index released this morning showed a slight expansion in August after three months of contraction while an official survey the day before showed that output jumped to the highest level in 16 months.

"The two series are both on an improving trend, serving as another confirmation of a much-strengthened growth momentum in the third quarter," Societe Generale's China Economist Wei Yao said in a research note.

Yesterday, an official survey by the China Federation of Logistics and Purchasing showed manufacturing expanded for the second month in a row, rising to 51.0 from July's 50.3. Both indexes use a 100-point scale on which numbers below 50 indicate contraction.

Copper for delivery in three months gained in London 1.6% to $7,211 a metric ton by 12:29 p.m. GMT. Prices jumped as much as 2.5%, the most since Aug. 8.

Copper for delivery in December added 1.6% to $3.2835 a pound on the Comex in New York, where trading is closed today for the Labour Day holiday.