The flurry of activity in BP shares at 1041 GMT (11:41 a.m. BST) saw the shares jump 4.8 percent to 494.9 pence, adding around 4.3 billion pounds ($7 billion) to the company's market value. At 1101 GMT (12:01 p.m. BST), they were trading 0.3 percent lower at 470.86 pence.

"(It) looks like a fat finger," said one London-based trader.

A London Stock Exchange spokesman said: "At 1141 (12:41 p.m. BST), price threshold for BP was breached so it went into an automatic five-minute suspension and then trading resumed as normal."

But he added: "I don't have any information on what could have caused it at the moment."

(Reporting by Tricia Wright, Blaise Robinson, Francesco Canepa, Vikram Subhedar and Atul Prakash; Editing by Lionel Laurent and David Holmes)