Events are starting to accelerate on the Sudanese border. Indeed, following the harassment of the Gazelle Force and aware of the inability to ensure effective defense, Generale Luigi Frusci (Governor of Eritrea) obtains the authorization of Amedeo di Savoia-Aosta to operate a gradual withdrawal of troops from mid-January. The objective is to abandon the various border posts, in particular the Kassala sector, to retreat to stronger defensive lines in the Eritrean mountains and thus block any further advance towards the heart of the Italian territory. The last phase of the withdrawal takes place on the nights of 16 and 17 January, when Generale Orlando Lorenzini ‘s II Brigata Coloniale leaves Kassala for the Keru – Biscia – Aicota sector. These movements are reveal by aerial reconnaissance and the deciphering of Italian messages, so General William Platt decides to precipitate the outbreak of the British offensive on 19 January 1941. 
The various air units are therefore ordered to join the advanced airfields before the afternoon of 18 January.  Five Vickers Wellesley of No.47 (RAF) Squadron, under the command of Flight Lieutnant Stewart, join the Blackdown field (around Gedaref) at 14h00. 
Regia Aeronautica is, however, not inactive as a bombardment on Summit airfield is reported. The attack, allegedly carried out in the morning by an Italian bomber, causes only damage considered negligible. Other attacks are reported against the stations of Haiya and Gebeit with, according to British documents, a limited success.  These events could have taken place between 03h15 and 11h50. 
The events in Kenya are still essentially marked by the attack on the El Yibo sector.
The Hartbees, No.40 (SAAF) Squadron, come into action at dawn attacking Italian positions to pave the way for South African troops. However, as a South African correspondent explains, the clash quickly turns into chaos :
“It was a battle of almost musical comedy confusion with the green South Africans at first unable to find their objective, then sending panicky signals for air and artillery support to crack the position when, with a little enterprise, we could easily have surrounded and forced surrender on the first day”. 
Thus, Brigadier F.A.L. Buchanan divided his troops into three elements:
- Force A composed of the 2nd Abyssinian Irregulars, equipped with several Natal Mounted Rifles vehicles and two radio sets must infiltrate the rear of the Italian positions in the night in order to cut off any retreat once the main attack is launched ;
- Force B with the B Company of the 1st Natal Mounted Rifles and five armored carriages of No. 2 S.A. Armored Car Company is in charge of a frontal attack ;
- Force C with the 1st Natal Natal Mounted Rifles C Company and two armored carriages must support Force B by a diversion attack on the flanks.
If Force A is able to reach its position, albeit only in the early morning with a first delay from the plan, Force B will fall further behind and launch its attack only at the end of the morning … while mistaking position. Italian troops are able to evacuate the endangered area while leaving a Banda screen to delay South Africans. The attack turns almost jokingly as several armored cars let escape part of the Italian Banda by confusing them with the patriots of the 2nd Abyssinian Irregulars because of a loss of all communications between the different Forces. The situation is, then, very confused since Brigadier Buchanan erroneously announces, around 14h30, that El Yibo is now captured and that he orders to push the attack towards El Sardu.
After a series of movements, the South Africans are aware of the error, but the troops are, then, exhausted and suffers from a lack of water, finally a withdrawal is ordered in the late afternoon to prepare a new attack the next day. In a message sent to the command of the 2nd South African Infantry Brigade, Lieutenant-Colonel McMillan states that :
“after conference today’s action realize enemy’s resources have increased and are considerable.”
For his part, Brigadier Buchanan asks :
“it most advisable that additional troops, ammunition, bombs, wire and water be immediately available, and (…) that El Yibo lugga presented considerable tactical problems (…) suggesting air co-operation, strong reinforcements of armoured cars and additional medical services (…) reported the unfortunate breakdown of communications”. 
According to Douglas Baker, a 1st Natal Mounted Rifles soldier :
“The preliminaries to the final assault meant that almost the entire regiment dressed in scanty khaki shorts and shirts to lay out all day and half the night in temperatures that had reached 145°F, and a heat that scorched not only your skin but heated up the lava rocks on which you lay. (…) The actual target was unclear and was presumed to have occupied in the first skirmish, which occured between 10:00 and 15:00 hours. This alone had tired out our forces throught heat exhaustion. Then it was found that El Yibo hadn’t been attacked at all ! The target lay a few miles on. By now the regiment was exhausted and had run out of the most precious of all commodities at this stage which was … water.” 
 I.S.O. PLAYFAIR (MAJ GEN), The Mediterranean and Middle East, The early successes againt Itay (to may 1941), Uckfield, The Naval & Military Press, coll. « History of the Second World War, United Kingdom military series », 2004, p.399 – 400 ; STEWART, Andrew. The First Victory : The Second World War and The East Africa Campaign. Yale University Press New Haven and London, 2016. p.148 – 155.
 SHORES, Christopher ; RICCI, Corrado. Dust Clouds in the Middle East – The Air War for East Africa, Iraq, Syria, Iran and Madagascar, 1940 – 1942. London : Grub Street, 2010 (Reprinted). p.96.
 No.47 (RAF) Squadron : Operations Record Book (Form 540 and Form 541). Kiew : TNA, AIR 27 / 463.
 No.223 (RAF) Squadron : Operations Record Book (Form 540 and Form 541). Kiew : TNA, AIR 27 / 1373.
 No.94 (RAF) Squadron : Operations Record Book (Form 540 and Form 541). Kiew : TNA, AIR 27/755.
 J.-A. BROWN, The War of a Hundred Days, Springboks in Somalia and Abyssinia (1940 – 1941), Johannesburg, Ashanti Publishing, 1990, p.107.
 ORPEN Neil. East African and Abyssinian Campaigns, Raid on El Wak : http://www.ibiblio.org/hyperwar/UN/SouthAfrica/EAfrica/EAfrica-6.html
 KATZ, David Brock. South Africans versus Rommel : The Untold Story of the Desert War in World War II. Stackpole Books, 2017.