Copper futures traded in London declined below a level of $7,000 for the first time in an 18-month period after data released in Europe and China, the biggest consumers, signaled that demand for the metal is flagging. July Copper futures traded on the London Metal Exchange fell 4% to $6,800 a metric ton, the weakest since October 2011, and they were traded at $6,840.25 earlier on Thursday Shanghai session.