POLICE swooped to arrest a second person yesterday after a female security guard at the Olympic Stadium was found to be in possession of explosives and a Class A drug.

POLICE swooped to arrest a second person yesterday after a female security guard at the Olympic Stadium was found to be in possession of explosives and a Class A drug.

A 43-year-old man was arrested at his home in Wales on suspicion of possessing an explosive substance. The development came after the arrest of the 40-year-old woman, who works as a dog handler, on Wednesday. She has been bailed until later this month.

Both are believed to be employees of security firm G4S, which has been guarding the Olympic Park site in Stratford since 2008.

The arrests are hugely embarrassing for London 2012 organisers Locog, who this week welcomed inspectors from the International Olympic Committee for the official completion of the stadium.

It also comes amid a bitter public row over profits between Locog and the British Olympic Association, and Tottenham ponder launching a legal battle over the controversial decision to award the Olympic Stadium to West Ham.

Police are not thought to suspect any terrorist motives, while G4S said its dog handlers were licensed to hold small amounts of explosives for training purposes.

G4S added in a statement: “Our canine services teams are highly effective because the dogs are able to train regularly using ‘live’ aids. G4S take breaches of operational processes very seriously and are assisting the police with their inquiries.”

A spokesperson for the Olympic Delivery Authority said: “There are robust measures to ensure the safety and security of the Olympic Park.”