An email sent to Sofia airport during a series of hoax alerts across Europe today was signed "the fighters of the Male State," AFP reported.

The email read:

"We, the fighters of the Male State, will make history with our actions today. Your feminist regime will remember this forever. The explosion will occur in 60 minutes. Today, your skies will turn red."

As reported earlier (14:38), similar messages were also sent to Italian airports.

While 20 false bomb threats across Europe will certainly raise concern, it is worth keeping in mind that this is just a fraction of the overall number of planes flying across the continent every day.

Some 27,400 flights were scheduled in Europe today, according to the European air traffic control agency, Eurocontrol.

The pilot of an Aer Lingus flight from Dublin to Rome that diverted to Évreux following a bomb threat (9:55, 10:07, 10:25) is being questioned by French authorities for initially refusing to land at a military base, according to media reports in France.

AFP, France24, Le Figaro and TF1 said that the pilot reportedly insisted on landing at a civilian airport, such as Beauvais or Nantes, prompting the French air force to intercept the plane with fighter jets.

He will now be "questioned under caution," local public prosecutor Rémi Coutin told AFP.

Aer Lingus has been approached for comment.

The four flights affected at Prague airport can now be confirmed as inbound flights from Athens, Dublin, Glasgow and Newcastle (11:16, 11:58).

A spokesperson for the Prague airport, told the Guardian that "an anonymous threat was received concerning the possible presence of explosive devices on board selected flights" arriving to Prague.

"In accordance with the Airport Emergency Plan, the Security Operations Command Center was activated under the direction of the Police of the Czech Republic.

The aircraft landed safely in Prague and were directed to remote stands.

Following their arrival, the Police of the Czech Republic conducted security searches of the aircraft for explosives, all with negative results. All passengers safely disembarked from the aircraft and received their baggage once all necessary security measures had been completed.

The situation had no significant impact on other airport operations. The threat is currently under police investigation. For this reason, we are not in a position to provide any further details."

Global airlines body Iata has "condemned … attempts to interrupt air transport," urging the relevant authorities to "find the origins of these hoax threats."

"Safety is the number one priority for the industry and we take all threats seriously," Iata's senior vicepresident for operations, safety and security, said in a statement.

"Meanwhile passengers should be assured that aviation security measures will continue to ensure the highest levels of public safety," he added.

Austrian defence ministry spokesperson Michael Bauer has confirmed that all affected flights in Austrian airspace were escorted by Eurofighters jets.

In a handy explainer, he said:

"What the Eurofighters can achieve in this scenario: They can observe the situation on site as the sole eyewitness and report any possible deviation from the flight path if the pilot has no radio connection.

If the aircraft is damaged but remains airworthy, the EF pilot can inspect the damage and provide assistance with information about the condition. Through visual contact with the pilot, they can at least support them in any case."

In a separate post, he confirmed there were three affected flights, which checks out with our tally (11:01).

Aegean Airlines confirmed a second plane from its fleet was also affected by a hoax bomb alarm, Greek daily newspaper Kathimerini reported.

We previously reported about a threat reported against their Thessaloniki to Milan-Malpensa flight (12:17), but a statement quoted by the Greek media says that its Athens to Vienna service, flight number A3860, was also disrupted.

In both cases, the reports were confirmed to be "baseless."

in Madrid

A spokesperson for Air Europa confirmed that one of their flights, flight number UX1027, which was scheduled to leave Madrid-Barajas for Paris at 8am local time today had also been affected by the hoax.

"A warning was received involving a flight from Madrid to Paris this morning," she told the Guardian.

"The flight hadn't taken off when the warning was received. All the relevant security protocols were activated for such cases. The plane was evacuated and checked, and it was found to be a false alarm. Passengers then re-boarded, the plane took off and landed in Paris without any problems."

Further to reports on "not credible" threats against Heathrow and Birmingham (15:04), a spokesperson for Heathrow airport told the Guardian that the report was assessed through "a multi-agency response" and "deemed not credible."

Here is the statement in full:

"Safety and security are our top priority. There are robust UK aviation security standards in place to assess and safely manage these types of situations.

Upon receiving the threat, a multi-agency response is initiated to assess the information and determine the response.

remains no evidence that the hoaxes are being orchestrated by a hostile state or terror group, investigators said, although inquiries across Europe into the incidents continue.

Air Serbia has confirmed to the Guardian that a bomb threat against its aircraft was reported to relevant authorities at Bucharest Airport, when the plane was en route to Romania (15:25).

In a statement to the Guardian, the airline said:

"After landing, the matter was taken over by the relevant Romanian authorities, which carried out procedures in accordance with applicable security protocols.

Following the completion of all checks, the security threat was assessed as unfounded, after which the aircraft was returned to regular operational service."

in Madrid

Spanish airline Iberia has just confirmed that two of its planes were among the three affected by false bomb alerts at Madrid airport (13:37).

The affected flights were IBE668 Milan – Madrid and IBE658 Rome – Madrid.

In a statement to the Guardian, the airline said:

"Iberia confirms that two of its aircraft were the subject of bomb threats this morning, which turned out to be false alarms.

The alerts were sent to Madrid-Barajas Airport and communicated to the captains of both flights, who proceeded to land in Madrid without any issues at around 10:00 a.m. today. Passengers disembarked without incident, in accordance with established security protocols."

Air Serbia has confirmed that one of its planes, a JU102 service from Belgrade, also received a bomb threat before safely landing in Bucharest, Reuters reported.

I will bring you more on this shortly.

The Press Association is reporting that two UK airports, Heathrow and Birmingham, received threats which were assessed as not credible, it is understood, as flights were diverted across Europe after a series of bomb alerts.

It is understood that operations at both UK airports have continued as normal, PA said.

A UK Government spokesperson said threats reported in the "early hours" of Thursday had been "resolved".

"It's right that authorities treat any potential threats seriously – the UK has one of the most robust aviation security systems in the world, with well-tested processes for dealing with any threats, as well as malicious hoaxes, like those we've seen this week."

The Met's Aviation Policing Command continues to monitor the situation and liaise with the relevant authorities."

UK transport secretary Heidi Alexander earlier told broadcasters that she was aware of "malicious hoax threats" affecting "a small numbers of flights across Europe."

The British Airline Pilots' Association has issued a statement on reported bomb threats to commercial flights across Europe, explaining the what happens after an airline gets a bomb threat.

BALPA Director of Flight Safety, Policy and Regulation, stressed that "aviation has historically been a target for bomb threats but the industry has well proved mechanisms for dealing with such threats."

"When a threat to an aircraft has been notified to the airline the threat is passed to a team of assessors. These assessors use standard processes to grade the threat and decide whether the threat is Red (credible), Amber (partially credible) or Green (not credible). Amber is not considered an appropriate assessment if the plane is airborne.

If the threat is assessed as not credible staff on the plane will not be informed of it.

However, when a threat is assessed as credible (red or amber) the flight crew will be informed immediately and they will carry out company procedures for a credible bomb threat."

Waites continued:

"From the moment the flight crew is notified of a credible bomb threat, commander of the aircraft – the captain - is in command and will make all the decisions, guided by the appropriate checklist, for the safety of their aircraft.

Usually if a plane is still on the tarmac that will mean an evacuation, and if it is in the air the priority will be to land the plane as soon and as safely as possible.

Pilots are highly trained and skilled professionals. Their expertise is invaluable in insuring passenger safety, and keeping aviation one of the safest forms of transport there is."

in Rome

A source at Aeroporti di Roma (ADR), which manages the city's two airports, confirmed Italian press reports that the hoax threats for the Helsinki-Rome and Dublin-Rome flights came from an anonymous email written in Italian with the subject heading "segnalazione minaccia" ("threat warning").

The email was signed on behalf of "Fighters of the Male State" claiming to be targeting a "feminist regime" and wanting to make its "mark on history".

The email, which was sent to ADR and affiliated businesses, also threatened to "turn the skies red" with explosions.

In an official statement, ADR said:

"The competent authorities are conducting the necessary investigations to establish the origin and circumstances of the threats, in accordance with established security protocols.

ADR Security played a key supporting role in managing both alerts, providing dedicated personnel to escort all vehicles operating beneath the aircraft, assist with baggage unloading operations, and carry out checks on both baggage and passengers."