Horrocks' men, while others note that German defences in the area were severely underestimated by First Allied Airborne Army intelligence. Particularly important was the failure to identify the remnants of two SS Panzer divisions, which after Normandy had been sent to the Arnhem area for rest and refitting; intelligence had stated that only "a few infantry units and between 50 and 100 tanks" were in the Netherlands. However, Ultra reports revealed the movement of the 9th SS and 10th SS Panzer Divisions to Nijmegen and Arnhem, creating enough concern for Eisenhower to send his chief of staff, Lieutenant General Walter Bedell Smith, to raise the issue with Montgomery on 10 September. Montgomery dismissed Smith's concerns and refused to alter the plans for the landing of 1st Airborne Division at Arnhem. Counter-attacks by Army Group B under Generalfeldmarschall Walter Model kept Horrocks' units on the defensive, and delayed their advance by forcing the British to halt and secure their flank. The terrain over which Horrocks' men had to move was also unsuitable, restricting the vanguard (Major-General Allan Adair's Guards Armoured Division) to a single narrow raised highway through flat or flooded countryside. The bridge at Nijmegen, just from Arnhem, was not captured by the 508th Parachute Infantry Regiment on the first day as planned, and XXX Corps had to assist in its capture on their arrival in Nijmegen two days later, causing a further delay of 36 hours. Horrocks was not personally blamed for the operation's failure although he himself writes in his autobiography that "If we were slow then the fault was mine because I was the commander", further stating that "the sense of desperate urgency was there all right. There could be no doubt about that, and it was not for want of trying that we failed to arrive in time. I don't believe that any troops in the world could possibly have fought better than the Guards [Armoured Division] and the 82nd U.S. Airborne Division when they captured the bridges at Nijmegen. But, after all we were cut off three times, and it is difficult to fight with one hand tied behind you." "It is always easy to be wise after the event but, knowing what I do now, I think it would have been better to have committed the 43rd Division on a different axis. Instead of passing them through the Guards on the 22nd, I should