Smoke grenade goes off at Chelsea's training ground

Chelsea have begun an investigation after a smoke grenade was let off at the club's training ground yesterday morning.

Players, officials and staff were forced to forced to evacuate the building in Cobham because of thick smoke, according to the Daily Mail.

"I can confirm an investigation is underway. It is an internal matter," a Chelsea spokesman said.

The club have so far refused to reveal whether or not a squad member was involved in the incident.