Mechelen Incident - The Warning By Sas

The Warning By Sas

That their deception plan seemed to prove that the documents were genuine, that day further increased Belgian anxiety; the next day they became convinced the situation was critical. In the evening of 13 January, a message from Colonel Georges Goethals, Belgium's Military Attaché in Berlin, included these words: "Were there tactical orders or parts of them on the Malines plane? A sincere informer, whose credibility may be contested, claimes that this plane was carrying plans from Berlin to Cologne in relation to the attack on the West. Because these plans have fallen into Belgian hands, the attack will happen tomorrow to pre-empt countermeasures. I make explicit reservations about this message, that I do not consider reliable, but which it is my duty to report". The "sincere informer" was the Dutch Military Attaché in Berlin Gijsbertus Sas who spoke with Goethals at about 17:00; his information always had to be carefully considered because he was in contact with a German intelligence officer who was an opponent of the Nazi regime, known today to have been Colonel Hans Oster.

General Van Overstraeten, the King of Belgium's military adviser, who was informed of the message at about 20:00, was astonished that the informant appeared to know about the capture of the plans. It had not been mentioned in any press report of the crash. It was possible that it was part of a grand German deception plan, but equally possible that it was genuine. Acting on the assumption that it could be taken seriously, Van Overstraeten altered the warning that the Belgian Chief of the General Staff Lieutenant-General Édouard van den Bergen had drafted and which was about to be sent to all Belgian Army commanders on 13 January; whereas it had stated that an attack on the next morning was 'probable', it now said an attack was 'quasi-certain'. Van den Bergen, who had in secret promised Gamelin to bring Belgium in on the allied side, then decided to broadcast (on a popular current affairs radio programme) that night at about 22:30, an immediate recall to their units of all the 80,000 Belgian soldiers on leave. "Phase D", as it was known, would ensure that their forces would be at full strength at the moment of the German attack.

This dramatic gesture was made without reference to the King or Van Overstraeten and without knowing the decision that had been taken to keep Germany in the dark about whether Belgium was in possession of its attack plans. Then, again without reference to the King or Van Overstraeten, Van den Bergen ordered the barriers to be moved aside on the southern border with France so that French and British troops could march in swiftly when they were called in, in response to the German attack. If the Germans had indeed attacked on 14 January, Van den Bergen would probably have been congratulated for his energetic decision-making. As it was, he fell in disgrace for acting without the King's permission, as King Leopold was the Supreme Commander of all the Belgian armed forces. Van den Bergen was rebuked so harshly by Van Overstraeten that the Belgian Chief of Staff's reputation never recovered; at the end of January he resigned. One of Van Overstraeten's complaints about Van den Bergen's actions was that he had given the Germans reason to believe that the Dutch had their attack plans.