'Oakfield' was an Allied deception plan designed to persuade the Germans that the Allies were preparing to launch amphibious assaults on the Italian coast at Rimini and Pisa, toward the north-western end of the Adriatic Sea and north-western end of the Ligurian Sea respectively (November 1943/January 1944).
Successor to 'Fairlands', the plan was thus designed to distract German attentions from the west coast of central Italy, where the Allies were preparing to launch their 'Shingle' landing at Anzio.
The overall deception scheme posited by 'Fairlands' was that the Allied intended to bypass central Italy and seek to cut off the German forces in the southern three-quarters of the peninsula by landing Lieutenant General George S. Patton’s US 7th Army at Pisa, and Generał dywizji Władisław Anders’s Polish II Corps plus British troops at Rimini. These two formations were then to advance to the east and west, and meet at Bologna.
'Shingle' was finally authorised on 26 December 1943, after a period of uncertainty, and represented an Allied attempt to break the stalemate along the 'Gustav-Linie' defences extending across Italy to the north of Naples. The landing was therefore to be committed at Anzio, which was not far from Rome and also close to the German line of communications along the Appian Way.
It was in November that 'Fairlands', the deception plan which Colonel Dudley W. Clarke’s 'A' Force had operated during the autumn, was transformed into the larger 'Oakfield'. This latter was initially designed to fulfil the dual tasks of persuading the Germans to withdraw forces from the main line to guard against landings that were threatened on each side of the Italian peninsula, and to lower their vigilance in the eastern part of the Mediterranean in aid of a planned Allied attack on the island of Rhodes. When 'Shingle' was authorised, 'Oakfield' was then enlarged into a major deception effort in support of that operation.
In its definitive form as created by the recently promoted Brigadier Clarke after he had visited the headquarters of General the Hon. Sir Harold Alexander Allied Forces in Italy command and of Lieutenant General Mark W. Clark’s US 5th Army, 'Oakfield' was schemed to suggest a pair of Allied landings on the north-west and north-east of Italy under the overall command of Patton’s US 7th Army. The former landing was to descend on the area of Pisa with the US 3rd Division and a British division, both launched from Naples, and be reinforced by two French divisions launched from Corsica and Algeria; and the latter landing was to descend near Rimini on the Adriatic coast by the Polish II Corps from the Middle East together with the US 82nd and British 1st Airborne Divisions from Sicily, and the US 88th Division from North Africa. Follow-up punch was to be added by the arrival of the fictional British XIV Corps from North Africa.
The concept successfully solved several real problems. The Pisa assault force was in fact the force genuinely earmarked for the Anzio landing, and 'Oakfield' provided cover for the fact of its assault loading at Naples. The Polish II Corps was actually departing Egypt for the Italian front, so the cover story accounted for its departure. Especially useful as an adjunct to the plan was a Royal Navy force, built around three battleships and the fleet carrier Illustrious, which was passing through the Mediterranean to the Far East. (This was the force that paved the way for 'Dundee' by the London Controlling Section, the UK-based deception organisation, to suggest that the task force’s longer-term object was support on an assault of Japanese-occupied Timor.) The Allies had at first been worried that the appearance of this naval force in the Mediterranean might alert the Germans to a landing in Italy, but now it was used as the covering force for the landing at Rimini, which had at first sounded implausible inasmuch as the area lay outside the range of Allied land-based tactical support warplanes.
'Oakfield' received all the trimmings it needed to 'prove' its reality. There were reconnaissance missions over the Pisa and Rimini areas, and further credibility was provided by beach reconnaissance efforts and occasional bombardments. Maps of the Pisa and Rimini areas were issued widely, as were pamphlets, some of them in French, on how to preserve works of art. Troops, aircraft and landing craft were moved into Corsica, and there was every appearance of major construction and extensive camouflage. Airborne training was expanded in Sicily and all available gliders were concentrated there. The wolf’s head insignia of the fictitious British XIV Corps began to appear from Algiers to Tunis, and invitations to the Christmas party at the corps headquarters were seen in Spain and Turkey.
Patton’s 7th Army was now a mere skeleton headquarters, and Patton himself was faced with a problematical future after he had slapped a soldier in the Sicilian campaign, but played his part to the hilt. The volume and tenor of its radio traffic suggested that the 7th Army was readying itself for major service, and Patton and his staff undertook a high-profile tour of the Mediterranean including Corsica, Malta and Egypt. Reaching the last on 12 December, Patton spent a week on tourism, lecturing garrison officers, visiting the naval base at Alexandria and, most importantly, reviewing the Polish troops on the verge of embarkation. A photograph of Patton and Anders, the latter sporting the 7th Army’s shoulder patch, found its way to an Istanbul magazine.
At a lower level there was a mass of radio traffic at and round all the ports from which the two landings were to be launched, and at tactical level 'Chettyford' was implemented to suggest an Allied attack on the eastern end of the 'Gustav-Linie' defences in the hope of causing the diversion of German formations from the western end of the line and thereby easing the task of the Allied left wing, which was to link with the 'Shingle' forces.
In the event 'Shingle' achieved total surprise, but this may not have been a direct result of 'Oakfield' for Allied air superiority was so great that the Germans had been unable to carry out any meaningful reconnaissance; the Germans believed that the Allies were fully engaged on land; and the reports of double agents were generally lost in the background noise of rumour and speculation. On 6 January Generalfeldmarschall Albert Kesselring, the Oberbefehlshaber 'Südwest', assured General Alfred Jodl, the chief of the operations staff of the Oberkommando der Wehrmacht, that there was no reason to expect any major Allied landings in the near future, and on January 21, the day before the 'Shingle' landings, Oberst Alexis Freiherr von Roenne of the Fremde Heere 'West', the intelligence organisation tasked with assessments of the Western Allies' forces, found no 'credible indications' of any deep flank attack by the Allies.