With it’s nose down, and travelling at phenomenal speed the Grandslam was hard to follow, it undershot the target by 30 yards and bored into the ground. After what seemed an eternity the ground rose up in a huge column of dirt and vegetation, Calder watched as an immense shockwave radiated out and slammed into the viaducts huge supports. Almost instantly 260 feet of viaduct simply crumpled and fell to the valley floor below. Several direct and near direct Tallboy hits caused further damage and the viaduct was out of action for the remainder of the war. No 617 crews returned to Woodhall Spa in jubilant mood to be met by Fauquier who, although happy at the result, was furious with Calder. Although he never forgave Calder, Fauquier did recommend him for a second DSO, which was duly awarded in June 1945. Despite 617's success, No 9 Sq had faired less well at Arnsburg, so the following day the unit returned for another try. Calder and Cockshot carrying Grandslams, the target was enveloped in cloud once again and only Cockshot dropped his bomb. Even with the rest dropping Tallboys the viaduct was left relatively undamaged. On March 19th No 617 Sq tried alone, this time they had six Grandslams and thirteen Tallboys. With clear weather allowing accurate aiming, the viaduct did not stand a chance. On March 21st twenty aircraft, including Fauquier and Calder with Grandslams, attacked the Arbergen rail bridge near Bremen. Bombing was accurate and the target destroyed. Although Grandslam and Tallboy were proving highly effective, there was concern at No 5 Group at the rate at which they were being used. It was decided that, upon reaching the target, four aircraft would bomb and their results observed before the next four would follow up if needed. This was agreed and tried on the next operation against the Neinburg rail bridge near Hanover on March 22nd. Of the twenty aircraft sent to Neinburg, 14 carried Tallboy and 6 carried Grandslam. The bridge was destroyed and the squadron returned with 2 Tallboy and 1 Grandslam unused. The following day an identical force bombed another rail bridge near Bremen with equal success. Heavy flak was encountered and the aircraft were harassed by Me 262 jet fighters resulting in several aircraft damaged but no losses. On March 27th a combined force of 115 aircraft flew to Farge, North of Bremen with 95 aircraft to bomb an oil storage depot and the 20 No 617 aircraft to attack the almost complete U-Boat pens. The U-Boat pens were a huge concrete structure, the largest in the world at that time, 1450 ft long and 300 ft wide with a reinforced concrete roof 23 ft thick. The importance of this target may be gauged by the fact that 14 Grandslam bombs were deployed for this operation. Once again heavy flak hampered aiming and a number of aircraft were damaged, the results though were spectacular. With two bombs passing clean through the roof and bringing down thousands of tons of rubble and masonry in the explosions. There would be no need for a return visit. With the German war machine in total disarray, the end of the European war was in sight. There was no let-up for No 617 Sq however, a return to Ijmuiden on April 7th by 14 aircraft saw ships and harbour installations hammered. On April 9th, 17 crews flew to Hamburg to bomb U-Boat pens, they were accompanied by Mustang and Spitfire fighter cover but no opposition was encountered. Aiming was good and bombing concentrated resulting in severe damage to pens and harbour installations. April 13th and 15th saw two attempts by No 617 and No 9 Sq to bomb the pocket battleship Lutzow and heavy cruiser Prinz Eugen, anchoed at Swinemunde, thwarted by further bad weather. A third attempt on 16th was concentrated on the Lutzow as the Prince Eugen was reported to have sailed. With two aborted attempts signalling the RAF interest in the target, Fauquier feared heavy fighter opposition and requested fighter cover to be provided....