Clearing the Channel Coast Clearing the Channel Coast was the task assigned , in World War II , to the 1st Canadian Army in August 1944 , following the Allied breakout from Normandy . The Canadian Army ' s line of advance took them from Normandy to the Scheldt . En route , they were to capture the Channel ports needed to supply the allied armies and clear the Germans from the Channel litoral and most of the launch sites for the V - 1 missiles . Most of the advance met with little more than sporadic resistance as the German 15th Army , wary of being outflanked and isolated by the rapidly advancing British 2nd Army , executed an orderly retreat north - eastwards towards the Scheldt . Resistance did occur in most of the Channel ports , designated on 4 September as " fortresses " by Adolf Hitler . Le Havre , Boulogne and Calais were subjected to full - scale assaults , as a result . A further assault was called off at Dunkirk , freeing resources for the clearing of the mouth of the Scheldt and the opening of the port of Antwerp . Two ports , Dieppe and Ostend were taken without opposition . Background . The German armies had strongly resisted the allied breakout from Normandy but , when it did occur , they had insufficient reserves of manpower and equipment to resist and no defence lines had been prepared in France . Consequently , they were chased out of much of northern France . Fighting in the Falaise pocket ended on or before 22 August 1944 and the 1st Canadian Army was freed to move north - eastwards up the coast . The 1st British Corps had started to advance eastwards from the River Dives along the coast on 16 September , as soon as German resistance faltered . Reconnaissance had been ordered on 19 August and the authorisation for a full advance and pursuit by the Canadians was issued on 23 August . It is a measure of the German disintegration that the 1st Polish Armoured Division were in Ypres on 6 September and Canadian units were at Dunkirk on 7 September , just fifteen days after Falaise , despite their reduced effectiveness after their Normandy battles . There was significant resistance , however , in the Canadian sector . Adolf Hitler had ordered that most of the Channel ports be established as " fortresses " and prepared for extended sieges . Since the allies needed the port facilities to supply their advance , they could not be sealed off and left in the rear . The Germans had established artillery positions capable of shelling Dover and threatening allied shipping . In addition , there were launch sites for V - 1 flying bomb s that were bombarding London . These , too , needed to be removed . The Armies . Allied . The 1st Canadian Army ' s make - up varied to meet changing demands but in general terms it was composed of the 2nd Canadian Corps and the 1st British Corps . Within these formations , at various times , were Czech , Polish , French , Dutch and Belgian units . After Normandy , the Polish and Czech formations were augmented by countrymen who had been conscript ed into the German Army . The 1st Canadian Army had been heavily involved in several hard fought operations in Normandy , resulting in depleted commanders and manpower at all levels . This was particularly serious in frontline rifle units . The 1st British Corps ( commanded by John Crocker ) , attached to the 1st Canadian Army , had its own weaknesses . Three divisions , the 7th Armoured , 49th and 51st Infantry Division s had not performed satisfactorily in Normandy and the two infantry divisions had been relegated to defensive positions on the bridgehead ' s eastern flank . The fourth division in the Corps was the British 6th Airborne Division which had landed in Operation Tonga on D - Day and , despite its lack of heavy weapons , remained defending the area . It had taken significant casualties and now its commander , Richard Gale , had been ordered merely to harry the German retreat and he intended to conserve its remaining strength as a basis for the rebuilding that was imminent . For this operation , 6th Airborne Division included the 1st Belgian Infantry Brigade and the Royal Netherlands Brigade ( Prinses Irene ) , which were to gain " operational experience in quieter sections of the line in the hope that ultimately they would return to their own countries and form nuclei around which larger national forces might be organized " . The 1st British Corps advanced along the allies ' coastal flank , with the 2nd Canadian Corps on their right . German . Most German divisions had been destroyed or shattered in the Falaise pocket . Those divisions deployed east of the allied bridgehead were , however , largely intact . German troops within the " fortress cities " were generally second - rate and included some Austrian and other nationalities that were not trusted enough to carry arms . Advance to the Seine . The 1st Canadian Army ' s advance to the River Seine was dubbed " Operation " Paddle " " . It had been hoped by the Allied commanders that a defeat comparable with the Falaise Pocket could be inflicted on the Germans by trapping them against the Seine and the sea . To this end , the US Third Army advanced northwards to Elbeuf , across the British 2nd Army ' s line of advance , to cut off the route towards Paris . This encirclement was only a partial success . Although much of its remaining transport and the bulk of its armour was lost west of the Seine , the Germans successfully held up the Canadians , protecting improvised river crossings . By this means , significant quantities of men and materiel were saved . The towns along the River Touques were evacuated by the Germans on or shortly before 24 August and the consequent capture of Lisieux ( about 45 kilometres east of Caen ) opened an important route eastwards . Next day , the next natural barrier , the River Risle was crossed just north of Brionne by the 11th Hussars , with other units close behind . The 6th Airlanding Brigade of the British 6th Airborne Division took Honfleur on the Seine estuary , but in general , progress along the coast was slower than inland , rivers being wider and more difficult to cross . Nonetheless , 6th Airborne Division occupied the west bank of the Risle from Pont Audemer downstream to the Seine on the 26 August and thus completed its tasks in France ; the Division returned to Britain on 3 September . Clearance of the last German units west of the Seine was completed on 30 August . Crossing the Seine . 1st British Corps put patrols across the Seine on 31 August . The advance to the Seine had outstripped the preparations of the Royal Canadian Engineers for bridging equipment and assault boats , but with hard work , newly assembled assault boats carried the 3rd Canadian Infantry Division across the Seine at Elbeuf on 27 August . Ferries for wheeled and armoured vehicles were in operation in the afternoon . Dieppe . Dieppe had been abandoned by the Germans before Hitler ' s order to defend it as a " fortress " had been received . It was liberated by the 2nd Canadian Infantry Division on 1 September . Its liberation had particular significance for that Division , as a result of the failure of the Dieppe Raid in 1942 . A ceremonial parade was held on 5 September . Despite demolitions , the port was cleared and in use on 7 September and a delivery of oil and petrol was shipped to Brussels on 9 September . Le Havre . Le Havre was subjected to a full - scale assault by 1st British Corps , supported by specialised armour and bombardment from land , sea and air . It was taken on 12 September after 48 hours ' assault , but the port needed lengthy clearance and repair . Boulogne . Boulogne was reached on 5 September but , by this time , the garrison was bound by Hitler ' s " fortress " order and would stand and fight . The city was protected by surrounding high ground and another full assault was made , this time by Daniel Spry ' s 3rd Canadian Division with extensive air and artillery support . The assault took six days from 17 to 22 September . Rocket sites . On 1 September , the last V - 1 was launched against London as the Canadians were moving through the launch areas . Calais and Cap Gris Nez . Calais was sealed off in early September , and Wissant was quickly captured , though an early attack on Cap Gris Nez failed . The assault on Calais itself opened on 25 September , and the town secured by 30th . A second attack on the Cap Gris Nez batteries opened on 29 September and the positions secured by the afternoon of the same day . Despite the strong defences , and although the city had been declared a Fortress , in the event its garrison needed little persuasion to surrender . This reluctance to fight to the end was repeated at Cap Gris Nez . Dunkirk . Although Dunkirk had been reached by 7 September , it soon became clear that the garrison would require a major effort to expel them and occupy a port that was largely destroyed . It was then judged to be a better use of men and materiel to clear the Germans from the Scheldt estuary and open the port of Antwerp , which had been captured intact . A brigade sized force was left to isolate Dunkirk , which eventually surrendered on May 9 , 1945 , after the general German surrender . This was a static operation , for the most part manned and led by the 1st Czechoslovak Armoured Brigade , in which Belgian Resistance members assisted with information and French Resistance members were converted to regular units . Belgium . Ostend had been omitted from Hitler ’ s list of " fortresses " and so was evacuated , despite its strong defences . The port had been demolished . The 1st Polish Armoured Division crossed the Belgian border and captured Ypres on September 6 , and reached the Ghent - Bruges canal on September 9 . The Scheldt . A major operation was required to clear the Germans from both banks of the Scheldt . Aftermath . Although Dieppe came rapidly into use , it could supply only a quarter of the needs of the 21st Army Group . The capture of Le Havre , Boulogne , Calais and Ostend only eased the allies ' supply problems after extensive clearance of debris and mines . Ostend remained restricted to personnel . Boulogne ' s role as a terminal for a Pluto oil pipeline ( " Dumbo " ) was of great benefit , however , becoming the Allies ' " . . . main supplies of fuel during the winter and spring campaigns " . In hindsight , it has been questioned whether the capture of the defended ports was worthwhile given the need for much effort to bring them into use and the greater potential benefit of Antwerp . The opening of Antwerp in November 1944 largely solved the allies ' supply problems . The capture of the French side of the Dover Straits removed the threat of the heavy artillery which had bombarded Dover for some years and endangered shipping in the Straits - the Royal Navy had particularly emphasised the need to remove this risk . Likewise , the V - 1 launch sites were overrun , reducing the threat to London . The Canadian Army ' s progress had not met the expectations of the Army Group commanders and its performance has been disputed since . It has been suggested that Crerar ' s illness in autumn 1944 provided a convenient opportunity to replace him during the critical and difficult Battle of the Scheldt .