A diary of the Longest Day

'Ouistreham was on fire and heavy shelling observed all along the coast.' The Second World War broke out 63 years ago this week. James Donald retraces his grandfather's part in the battle that helped to end it

"We emplaned by 1900 hours. It was very quietly and efficiently done, and very well timed. The take-off was perfect and the journey as far the French coast, quiet and unmolested." The start of my grandfather's record of his journey to France makes it sound like he was going on holiday. But then his mood alters: "On reaching the coast the picture changed with dramatic suddenness... the journey became 'rocky'." It is not surprising that the journey was "rocky" – it was D-Day, and Major Ian Gilliland was in a Horsa glider with 29 other soldiers, under attack from the German defences. Today, the only excitement on this sleepy flank of Normandy is the arrival of the ferry from Portsmouth. Ouistreham is a small fishing port that most travellers miss as they accelerate off the ferry and aim south; a shame, because the port provides a serene introduction to France – as well as some good seafood. But on 6 June 1944, "Ouistreham was on fire and heavy shelling was observed all along the coast. Flak could be seen from many points. On being released from the tugs, the noise of gunfire was very clear."

My grandfather was a Royal Army Medical Corp (RAMC) officer with the 195 Airlanding Field Ambulance. This was part of the 6th Airborne division, which had been involved in several vital operations to help ensure the success of the beach landings of Sword, Juno, Gold, Omaha and Utah, and to form a pivot for the Allies' further advance.

The vocabulary of conflict is austere. Even before his glider was safely down, "One plane was hit and 1 RAMC OR [other rank] killed. Two crashlanded and 1 RAMC Sgt sustained a fractured pelvis."

His glider landed in the fields next to Ranville, eight miles northeast of Caen at 9pm – at the end of "the Longest Day".

Armed with a copy of the original operational map, I went to retrace my grandfather's steps.

One of the most important of these operations had begun in the early hours of 6 June. The aim was to capture two bridges, one over the Caen Canal, and the other, next to it, over the river Orne – about six miles north of Caen. They were east of the landing beaches, and their capture would prevent the German forces from sending back reinforcements to attack the Allied troops landing on the beaches. It would also allow the Allies to go forward, once they had established a beachhead.

Six gliders, each containing 30 men, under the command of Major John Howard, were released from a convoy of Halifax bombers; it was hoped the Germans would mistake them for planes that had been destroyed by anti-aircraft fire. Three had landed close to the bridge over the Caen Canal 10 minutes after midnight. The troops burst out of the gliders after their rocky landing. They captured the bridge within 10 minutes, although with the loss of Lieutenant Denholm Brotheridge, who was Platoon Commander and was leading the charge, making him the first British casualty of D-Day.

Stone posts mark where the gliders landed. I stood there and imagined how I would have acted if I had been in one of them.

Two other gliders landed next to the bridge over the river Orne, and that bridge was captured too. A radio operator sent the signal back in code that both bridges were under Allied control: "Jam and ham." The sixth glider landed miles away, behind what became enemy lines, but the troops managed to escape.

The bridge over the canal has been renamed Pegasus Bridge in memory of the attack – the Pegasus is the symbol of the Airborne Division. The Café Gondrée next to it has a large sign proclaiming it as the first building liberated in France; Ranville became the first town to be freed from German occupation. The owner had hidden a cache of Champagne in the garden when the Germans invaded, and he produced this once his establishment was liberated.

Across the bridge towards Ranville is Memorial Pegasus, a museum opened by Prince Charles in 2000. It is constructed in the shape of a glider, and has many mementoes from the attack – the biggest of which is the original bridge, complete with war damage. The bridge was replaced by a new pont in 1994, and was subsequently stored in a lorry park, but has now been restored and placed on display in the garden of the museum. There are plans to make a lifesize replica of one of the Horsa gliders for the 60th anniversary of the attack in 2004.

The museum also includes a model of the German HQ building at Ranville, which was captured by 13 Parachute Battalion at 2.30am on the early morning of 6 June. On 7 June, my grandfather moved in to the same building to set up a Medical Dressing Station (MDS), and found it "indescribably filthy". Its previous occupants, he noted, "had obviously left in a great hurry. By 1100 it was clean, the staff divided into departments and ready to work. At once casualties began to arrive. By midnight 154 cases had been admitted, 23 of which had required urgent surgical intervention."

In such circumstances, promotion could be brisk. By the next day, my grandfather had taken charge of the MDS and become Lieutenant Colonel Gilliland because his commanding officer had been injured. His work there was often under heavy fire; on the same day, in rather an understated way he wrote: "The MDS was mortared for most of the afternoon, which made the continual evacuation rather difficult. At 1800 hours heavy direct shelling started. One direct hit on the officer's mess. 3 RAMC ORs were casualties. The Surgical Theatre was then moved to the basement for safety."

Even four days into the invasion, with Allied reinforcements swarming into Normandy, life in the field hospital was fraught with danger. "D+4 was a difficult day. The Germans were clearly visible all morning in the glider field opposite the MDS. On one occasion tracer bullets were seen going down the road outside and the German forces were so near at midday that all secret documents were placed in a fireplace ready to destroy. At 1600 tanks arrived and cleared the Germans."

My grandfather also treated German casualties. One SS officer was so badly wounded that he needed a blood transfusion. He asked my grandfather for a guarantee that there was no Jewish blood in what he was about to be given. My grandfather could not: blood was taken from all the troops in the medical unit, and his sergeant was Jewish. The Nazi officer refused the transfusion, and died of his wounds.

The house is still there – it was used as a school for disabled children after the war, and was recently sold to a local electricity company, which uses it as it headquarters and workshop. It is in the east of the town, and to reach it from the Memorial Pegasus, you go through Ranville, past the plaque in memory of the 13th Parachute Battalion which liberated the village, and it can be seen from the small parking area.

The Nazi flag that had flown outside before its capture was exhibited in the Mayor of Ranville's office for years. It is now on display in the Memorial Pegasus, along with the major's sword, his medals and the mascot puppet he had with him when he was parachuted into France.

Despite the difficult conditions, there were still distractions for my grandfather and his staff. He recorded that: "The 17th June started by admitting a woman of 23 in labour. Uncomplicated delivery of full-term male child occasioned much interest among the staff. A good cot was made from a compo ration box. A small christening service was conducted in the morning by the padre."

Six days later, "A unit concert was held in the evening in the barn, and proved a very great success, many spontaneous turns being given, in spite of sporadic mortar fire." Morale was considered important: at the end of June, he records that "40 seats were given to the unit for a picture show on the beaches."

The line of the 6th Airborne was never broken. But over the months while they defended it, they suffered 4,457 casualties, of which 1,748 were listed as killed or missing in action. Most are buried in the Commonwealth War Graves Cemetery at Ranville. Opposite the gate to the cemetery is a monument raised by the people of Ranville. A map shows where the airborne landings took place, and gives the names of all the regiments and units that took part in the campaign that changed the face of Europe.

Lt Col Ian Gilliland died in 1975. He was mentioned in dispatches.

Thanks to Major Jack Watson MC for unearthing my grandfather's official monthly reports for June and July 1944. Major Watson served with the 13th Parachute Battalion, and was involved with the liberation of Ranville.

The Memorial Pegasus is at Avenue du Major Howard, 14860 Ranville (00 33 21 31 78 19 44, www.normandy1944.com). It opens 10am-6pm daily, from 1 February to 15 December. Admission is €5 (£3.30).