Counter terrorism investigators are linking a device found in Glasgow on Wednesday with three devices found yesterday in London, police said.

Several buildings at the University of Glasgow were evacuated as army bomb disposal experts carried out a controlled explosion on a suspicious package found in the mailroom.

Commander Clarke Jarrett from the Met’s Counter Terrorism Command said: “Due to similarities in the package, its markings and the type of device that was recovered in Glasgow, we are treating it as being linked to the three packages we’re investigating in London.”

A series of security alerts followed across the UK throughout the day, as police were called out to suspicious packages in Edinburgh, Colchester and London.

Parcels found at Royal Bank of Scotland (RBS) headquarters in the Scottish capital and the Essex University campus, both briefly evacuated, were found to pose no risk to the public.

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Officers also responded to a report of suspicious package at an entrance to the House of Lords shortly after 4pm, but it was quickly found to be a false alarm.

Metropolitan Police cordoned off an area near Hammersmith Broadway in west London at 6pm following reports of yet another potentially dangerous package, but it was found to be a bag and deemed non-suspicious.

A British Transport Police spokeswoman told The Independent officers were also called to investigate an incident at Bayswater underground station after a bag was thrown from a train at the station.

Wednesday’s security scares followed the discovery of explosive devices at three London transport hubs on Tuesday, as counter-terrorism officials continue to try to identify a motive or suspect.

Metropolitan Police said it was liaising with colleagues in Scotland about the device found in Glasgow. “We are working very closely with our colleagues from Police Scotland and both investigations are being run in tandem,” said Ms Jarrett.

She said the package detonated in Glasgow contained a “similar-type device” to the three small improvised explosive devices (IED) found in the capital.

Police at Glasgow University follow suspicious package evacuation

The packages mailed to Heathrow Airport, Waterloo station and London City Airport were posted with Irish stamps and had Dublin as the return address, prompting Irish police to join the investigation.

Security sources suggested the Irish insignia may have been a “concerted attempt” to make them appear as though they were posted from Ireland, but could not rule out that they had been.

Deputy assistant commissioner Dean Haydon, the senior national coordinator for counter-terrorism policing, said on Wednesday that no link had been made with Irish dissidents at this stage.

“We are talking to our Irish counterparts but at the moment there’s nothing to indicate motivation of the sender or ideology, so I cannot confirm at the moment if it’s connected to any Ireland-related terrorist groups,” he said.

Emergency services at Glasgow University (Alamy Live News.) (Alamy)

In a bid to identify a suspect, Mr Haydon said forensic teams are scouring the packages for DNA and fingerprints in an effort to identify the sender.

He stressed they are small devices “not designed to kill”, but said they show “some degree of sophistication” that would require a certain level of capability to produce.

Scotland Yard released images of the London packages circulated to transport workers and postal sorting staff across the country.

Package sent to Heathrow caught fire (AFP/Getty)

Commander Clarke Jarrett, head of the Metropolitan Police Counter Terrorism Command, said police had not received any further reports of devices in London, but had “issued extensive advice to transport hubs and mail sorting companies to be vigilant”.

Police Scotland’s assistant chief constable Steve Johnson said the package found at the University of Glasgow was “not opened and no one was injured”.

He added: “The emergency services were alerted and several buildings within the estate were evacuated as a precaution. A controlled explosion of the device was carried out this afternoon.”

Officers in Edinburgh were called out to RBS Gogarburn House and ordered the building be cleared shortly before 11am, but the package was found to contain only “promotional goods”.

Students at Essex University’s Colchester campus were evacuated around 11.50am after a suspicious package was found. The Ministry of Defence’s Explosive Ordinance Disposal (OED) team discovered the item package “posed no risk,” causing the cordon to be lifted at 4pm.