London bomb threats - live: Irish police assisting after explosive packages sent to transport hubs in capital

Security expert Will Geddes claimed the security incidents were to be expected given the current threat level.

“We’ve not had a significant incident for quite some time,” he told the Press Association. “To be honest, we were anticipating something happening. Transportation hubs have always been on the agenda for any kind of terrorist group.”

“The biggest threat you’re always going to have is someone leaving an IED in an unattended bag.”

Speaking about photos posted on social media claiming to show some of the packages involved, Mr Geddes said: “It would appear that they have been hand written addressed envelopes, which in itself will be potential forensic treasure for the investigators to try and track and trace who might have been the originator.”

One man among a group of Network Rail staff gathered outside the company’s office at Waterloo said he was the individual who found the package at the station.

Asked about the discovery, he told the Press Association: “I’m sorry, I’ve been told I can’t talk about it.”

The BBC’s Daniel Sandford has shared higher-quality images of two of the discovered IED packages. They appear to show bogus information scrawled in the senders’ name and address box.

If you just catching up with the security alerts in London, here’s a brief timeline of Tuesday’s discoveries.

9.55am: Heathrow’s Compass Centre was evacuated after a suspicious package was reported to police. It was opened by staff, causing the device to initiate, resulting in part of the package burning.

11.40am: a second package was discovered in the post room at Waterloo station.

12.10pm: A third package was found at Aviation House at London City Airport, leading workers in the building to be evacuated as a precaution.

At the end of the afternoon, around 4.30pm, the Metropolitan Police revealed the suspicious packages – all A4-sized white postal bags containing yellow Jiffy bags – had been assessed to be small improvised explosive devices.

Chris Phillips, the former head of the National Counter Terrorism Security Office, says he would have expected major transport hub offices to have had scanning processes in place to prevent IEDs being opened.  

“This shouldn’t actually get to the desk of anyone,” he told the BBC News channel. “There may be others out there, and these things will, potentially, take your hand off if you open them incorrectly.”

“Usually these things come in waves,” he added. “Everyone needs to be aware of this. Hopefully the police will put out what these packages look like so people have got an opportunity to stop them before they get opened.”

 Sky News’ Ireland correspondent Stephen Murphy says sources in both Dublin and London are “downplaying” the possible connection to Irish dissidents.

One of the photos posted on social media of the package sent to Waterloo station appears to show a senders address as Bus Eireann, Dublin. But the bus operator said police had not been in touch, with a spokeswoman telling the Press Association: “Bus Eireann are currently not aware of this and we have no further comment.”