A third was found at Waterloo station. All three devices have been made safe, the Metropolitan police has confirmed.

Counter terror officers are linking the incidents. No arrests have yet been made and enquiries are ongoing.

All three packages were described as A4-sized white postal bags containing yellow Jiffy bags and assessed to be small improvised explosive devices.

The Met said all three appeared capable of “igniting an initially small fire” when opened.

Officers were called to reports of a suspicious package at The Compass Centre in Nelson Road, Hounslow, near Heathrow airport, at 9.55am.

Staff opened the package causing it to ignite. No one was hurt and the building was evacuated as a precaution while specialist officers made it safe.

The building is separate to Heathrow airport and flights were unaffected.

At 11.40am, British Transport Police officers are called to reports of a suspicious package in the post room at Waterloo station.

Again, specialist officers attended and made the package safe. No one was hurt. Train services continued as normal.

Police were called to reports of a third suspicious package at City Aviation House near London City airport at 12.10pm.

Staff were evacuated as a precaution. Specialist officers made the device safe and there were no reports of any injuries.

DLR services to London City airport were temporarily suspended but there was no impact on flights.

The Met has issued advice to transport hubs across London to ensure staff and travellers are vigilant to any potentially suspicious packages and report them to police.