A new phase
After the British-Canadian offensive (Battle of the Bulge) was completed on 9 November 1944, the Hollands Diep and Amer rivers and the Bergsche Maas canal formed the new front line. This was guarded by units of the 1st Canadian Army, including the 1st Polish Armoured Division of Major General Stanisław Maczek, until the spring of 1945.

Support points
During the first period, which lasted until 20 December, the Polish troops were responsible for the Moerdijk-Geertruidenberg sector. Maczek had too few troops to man the front everywhere, so a series of support points were chosen, including Blauwe Sluis and Lage Zwaluwe. The residents of these places were subject to a curfew, and there was no real freedom. The nine battalions in the Polish division each occupied one of these support points for one week in turn. When they were not active, they could recover in places further south. Patrols walked between the strong points to prevent German troops from secretly crossing the water. During the day, this was the task of the Dutch Home Forces, the BS, which consisted of volunteers who were mostly, but not exclusively, former resistance fighters. The six companies in West Brabant (approximately 600 men) formed the 3rd Battalion and were under the responsibility of Major van der Poel in Breda.

Boring and dangerous
From Lage Zwaluwe, one group of Polish troops always headed west to the main road to Rotterdam, while a second headed east to the beginning of the Gat van den Ham. During the day, BS patrols followed approximately the same routes right along the bank of the Hollands Diep. Operating the posts and walking patrols was not only boring and unpleasant in the harsh winter conditions, but there were regular incidents with German groups that sometimes resulted in deaths and injuries. During one fight of fire, German soldiers cut off the tongue of a member of the BS to prevent him from calling for help, whilst in another both Polish and German forces were killed. The area around the blown-up bridge at Keizersveer was in particular an area where ​​such confrontations took place.

Until the bitter end
The river front was therefore anything but sealed, and one German patrol even managed to reach Dorst during a long winter night, fifteen kilometres into the hinterland. But Polish, Canadian and British commandos also regularly crossed over into the Land van Heusden en Altena. The situation remained restless in places close to the front until April 1945, by which time the Polish and Canadian forces had already left and were fighting in Germany.