Whilst the 4th Parachute Brigade had been attacking the Dreijenseweg, the 7th King's Own Scottish Borderers had been holding a defensive position around LZ-L, on which the gliders of the 1st Polish Independent Parachute Brigade Group were to arrive. The Brigade's vehicles and anti-tank guns were to land here whilst the main parachutist element was to drop on DZ-K, a mile to the south of Arnhem Bridge. This latter lift was cancelled, however, as dense fog had descended on the USAAF airfields from where they were to take-off. The RAF glider airfields were similarly shrouded, however the fog eventually cleared and so this segment of the Third Lift was able to proceed.
In comparison to the 10th and 156th Battalion's, the 7th KOSB had experienced little in the way of enemy interference around the Landing Zone, despite being heavily shelled at noon. During the morning a number of German fighter aircraft appeared overhead and proceeded to strafe their positions. Any damage they caused was superficial, yet the sight of German aircraft flying unchallenged over the battlefield, when the Allies had almost complete air superiority at that stage in the war, came as something of a surprise to the British troops.
Time passed and H-Hour for the Third Lift came and went; as with the Second Lift on the previous day, the 1st Airborne Division knew nothing of the delayed take-off, and so could only wait until the airborne armada eventually materialised. This delay left the 4th Parachute Brigade in an awkward position. The 10th and 156th Battalions were in the process of falling back on LZ-L, and they were being closely followed by enemy troops and armoured vehicles, thus raising the prospect of the zone being overrun before the gliders could land.
To further complicate matters, the Brigade had to withdraw south of the railway line to rejoin the remainder of the 1st Airborne Division in the hope of advancing towards Arnhem from there; the failure of the 11th Battalion to capture the pivotal Heijenoord-Diependal high ground had not yet been reported. There were only two possible crossing points for their vehicles; the stations at Oosterbeek and Wolfheze, and it was assumed that both of these areas, if they had not done so already, would soon fall into German hands and so one or the other had to be secured with the utmost speed. The closer Oosterbeek Hoog station was on a junction with the Dreijenseweg, which was clearly under German control. The Brigade planned to attack this area, however Dutch Resistance members reported that a large formation of enemy troops were closing on the British from the west; this was Kampfgruppe von Tettau, with an infantry strength approaching that of a division. Alarmed at this news, the Brigade instead decided to take the roundabout route to Wolfheze and secure the crossing before this new formation arrived. With the 7th KOSB unable to move from the Landing Zone and the two parachute battalions being pushed against the railway line by an enemy advancing from three directions, the position of the 4th Parachute Brigade was clearly in some jeopardy.
Back in England, forty-three gliders were towed into the air at midday and began their flight to Arnhem, eight of which carried those elements of the 1st Airborne Division which had failed to arrive on the previous lift. Of these, only thirty made it to the Landing Zone; the rest having to abort or prematurely cast-off for one reason or another, one of gliders, however, received a direct hit from flak and broke apart, killing all aboard.
Also heading for Arnhem were one hundred and sixty-four RAF transport aircraft carrying supplies. Sadly, neither this nor the glider formation managed to link up with its fighter escort, leaving the slow and unarmed aircraft at the mercy of no less than five German flak batteries. Flying at only nine hundred feet, they were a perfect target and ninety-seven aircraft, over two-thirds of those involved, were damaged by enemy fire, and nine Stirlings and four Dakotas were shot down at a loss of fifty-two men. Nevertheless, the aircraft boldly flew into the flak and dropped their supplies accurately. It was during this process that Flight-Lieutenant Lord was killed whilst performing feats that would see him posthumously awarded the Victoria Cross. The great tragedy of these valiant efforts was that Germans had overrun the supply dropping point, and due to the radio blackout there had been no means of informing the RAF of this fact. Therefore, not only were the supplies denied to the 1st Airborne Division, but the Germans were able to make full use of them against their intended recipients. The Germans in the Arnhem area, like so many others elsewhere, had been short of food and ammunition, and so they were naturally delighted with these packages which fell from the sky, many enjoying the taste of chocolate for the first time in years.
The gliders were flying at a much higher altitude than the supply aircraft and so were less vulnerable to the anti-aircraft fire. When they cast-off and began their slow descent, however, they had to come down through a barrage of flak and small arms fire. Several gliders were hit but only one was brought down; its nose was shot off and an internal explosion caused the glider to crash, emptying its cargo of several Polish soldiers and a Jeep over the Landing Zone. The 7th KOSB were unable to prevent the Germans from firing at the gliders whilst they were in the air, but once below the cover of the tree-tops they were able to land without any interference. Unfortunately many of the gliders came down heavily and much of the equipment they carried could not be salvaged. Only three of the Polish Brigade's ten Anti-Tank guns that had left England were in serviceable order. Although few men were involved in this landing, the price had been high as nine of the ninety-three Polish personnel involved had been killed or would die as a result of their injuries.
Two of the gliders landed two miles away on LZ-S, which had been overrun by German soldiers. Both of these had made forced landings on the Second Lift, but their pilots had not been briefed that they were to land on a new zone with the Third Lift. It is believed that the one group may have been able to slip away to rejoin friendly troops, however the other, part of the 7th King's Own Scottish Borderers Mortar Group, were quickly surrounded and taken prisoner.