THREE packages containing explosives have been found at London airports and a train station.

The "small improvised explosive devices" were found in A4 postal bags at Heathrow Airport, London City Airport and Waterloo station.

However no-one has been injured.

A counter-terrorism police investigation has since been launched and the incident is being treated as a "linked series".

Officers from the Met's Counter Terrorism Command have added that they are "keeping an open mind regarding motives".

The first package, found at Heathrow, was reported to police at around 9.55am.

When opened by Heathrow staff the device burst into flame.

The Compass Centre office building in Heathrow's ground was evacuated and remains closed.

Two more devices were then found over the next three hours ­—

one at Waterloo station, discovered at around 11.40am, and another at City Airport, at around 12.10pm.

Neither package was opened and both have since been "made safe".

An area of the Waterloo station was cordoned off and staff members were temporarily evacuated from the airport's City Aviation House.

However no flights or trains were affected.