If you have read my previous posts about proposed raids on Alderney then you will understand why this blog post could have had a multitude of titles! As with the other proposed operations this one was very much the brainchild of and driven by Lord Louis Mountbatten.

This operation was a sub operation of Operation Constellation the others were Operation Coverlet against Guernsey and Operation Condor against Jersey.   In this blog post I will be dealing with Concertina. I will deal with the other operations in future posts.

The previous blog posts are Operation Attaboy (1941) which you can find here and Operation Blazing which (1942) which is here . If you haven’t already read these I would read them first starting with Attaboy then Blazing. This will give you a good background to how Constellation and then Concertina came about.

I considered “Operation Concertina – third time’s a charm”, “Alderney here we go again or not as the case maybe!” or just a graphic of Alan Brooke shouting “Oi Mountbatten no!”. Anyway enough of being flippant and on with the story.

Having read those you may well be wondering why on earth they were considering what looked like a very similar operation to what had been proposed in February & March 1941 and 1942. This is especially pertinent as they had evaluated the Islands as being “of no strategic importance to either us or the enemy.” as early as mid 1940 and an assessment that was repeated almost every year thereafter.

At the Casablanca Conference in January 1943 the possibility of a large-scale raid on the Channel Islands was again discussed.    This was to be given the name Operation Constellation, the sub operations were Operation Coverlet against Guernsey, Operation Condor against Jersey, and Operation Concertina against Alderney.  

On 17 January 1943 Mountbatten, at the Joint Chiefs of Staff 53rd meeting, made the very bold statement that “He would capture the Channel Islands without help from the United States.”1

On 22nd January 1943 a note by the Combined Chiefs of Staff was presented for cross Channel Operations.  Part of this was to undertake “Small scale amphibious operations, such as the progressive reoccupation of the Channel Islands. (Note: Raids are already adequately taken care of by the existing organisation.)”2   The note suggest that such a raid should be along the lines of Dieppe. We all know how Dieppe ended!

At the meeting on 23rd January 1943 the American President, Franklin D. Roosevelt, asked about the dates proposed for the operations.  In his reply Mountbatten said that the date for the Channel Island operations had been chosen so as to fit in with Operation ‘Husky.’3  The difficulty being the number of landing craft that the Americans required for ‘Husky’ some of which would need to come from the British Channel Assault Force.4

Mountbatten later goes on to explain that the landing craft resources would only permit an initial assault by 2 brigade groups with an immediate follow up of one brigade group with some armour. This could only be increased with American assistance.  This the Americans declined to help with this as they required all their landing craft for ‘Husky.’    

Despite the lack of support from the Americans the feasibility of a large-scale operation to retake one or more of the Channel Islands continued.  On 17th February 1943 a memorandum was produced by the Chief of Combined Operations, Mountbatten, for the War Cabinet Chiefs of Staff Committee and the name Operation ‘Constellation’ appears.5   It refers to an outline plan for an operation against Alderney. Regarding the other islands, he states that “examination has not yet reached a stage when it is possible to say that attacks on Guernsey and Jersey are practicable.”   The attached outline plan refers to ‘Constellation’ as a whole but the operation against Alderney as a sub operation ‘Concertina.’  The sub operation against Guernsey was named ‘Coverlet’ and Jersey was called ‘Condor’ although these names are not mentioned in this plan.

Interestingly for the first time, having previously been discounted, the plan to retake one of the Channel Islands, specifically Alderney, is referred to as “strategically desirable.”  The plan records that the reason for this is that it would assist with ‘Husky’ because the Germans would become nervous of a landing on the Cherbourg peninsula.  This would also prevent them from moving men and equipment away from France.

It also notes that ‘Concertina’ would have an impact on the proposed, but never enacted, Operation ‘Lethal’ the capture of the U-boat bases in the Brittany peninsula of German-occupied France and Operation ‘Hadrian’ combined operations attack to seize Cherbourg.

The plan notes that if ‘Concertina’ went ahead it would mean that ‘Lethal’ would not be impacted but that ‘Hadrian’ would probably become more difficult because the Germans would strengthen their defences.

The memorandum of 17th February notes that the preliminary air bombardment of Alderney would involve the following:-

  • Night of D-2/D-1 the island is attacked by a force of 500 to 600 heavy and medium bombers.
  • D-1 daytime daylight attacks to be carried out by American heavy bombers.
  • On the night of D-1/Day the island is again attacked by a force of 500 to 600 heavy and medium bombers.   

This would be an incredible amount of bombs to be dropped on such a small target.   At the lower end this would be somewhere around 2,300 tons to 4,500 at the higher end depending on the mix of heavy and medium bombers.

The Naval force was to be:-

  • One Monitor
  • 1 AA Cruiser
  • A/S Destroyer escort
  • 8 Hunt Class destroyers
  • 12 M.T.B.
  • 12 M.L.
  • 6 L.S.I. (H)
  • Landing Craft as required for the force
  • 6 M.S. Trawlers
  • 6 A.S. Trawlers
  • One Boom Defence Vessel

The memorandum considered that the military force required would be:-

  • One Brigade Group   
  • Two Commando Units
  • One Field Company R.E.
  • Two Heavy and two light A.A. Batteries
  • One  Battery of 4.5” Gun Howitzers for coast defence
  • One Squadron tanks
  • Ancillary units

Apart from the bombers they would require:-

  • One Squadron A.S.V. Aircraft
  • One Squadron striker aircraft – torpedo and bomb
  • Forty to fifty squadrons of S.E. fighters
  • At least two aircraft of P.R.U.

This memorandum was discussed at the War Cabinet Chiefs of Staff Committee meeting on 19th February 1943.6 Mountbatten said that he had come to the conclusion that the only option was Alderney given the discussions in Casablanca, referred to above, because of the requirements for landing craft for ‘Husky’ and the Americans requirements.

As with its forerunner “Blazing” Sir Alan Brooke, Chief of the Imperial General Staff, thought the plan unsound feeling that the peculiar granite construction of the island that the bombardment would be unsuccessful.  Sir Charles Portal, Chief of Air Staff, on behalf of the RAF doubted that it would bring about the air battle predicted by Mountbatten.

The meeting went on to approve the operation being further investigated but that a raid on the submarine pens in L’Orient was also to be investigated.

On the 19th February 1943 Brooke notes in his diary a long COS meeting.

A long COS meeting at which Dickie Mountbatten gave me a heap of trouble with a proposed attack on the Channel Islands which was not in its proper strategical setting and tactically quite adrift .

Sir Alan Brooke, Chief of the Imperial General Staff

At a subsequent meeting on 1st March 1943 the meeting noted “the Committee took note of a report from the Chief of Combined Operations, Mountbatten, on the result of a reconnaissance of an island in the “Constellation” group.7

After this mention of “Concertina” dries up and it is likely to have been killed off by that final meeting and the lack of available landing craft or crews for them as well as the unwillingness of the Chiefs of Staff.   

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I will be adding more as time permits. Thank you for taking the time to read this, and I hope you enjoyed it. Please share it on social media or add a comment if you did. Feedback is always appreciated.

Also happy to be contacted with questions about the war in the Channel Islands, media appearances, podcasts etc.

© Nick Le Huray


  1. United States Joint Chiefs of Staff –  https://www.jcs.mil/Portals/36/Documents/History/WWII/Casablanca3.pdf   page 371
  2. United States Joint Chiefs of Staff –  https://www.jcs.mil/Portals/36/Documents/History/WWII/Casablanca3.pdf   Page 113
  3. Husky was the operation to take Sicily.
  4. National Archives – CAB 80. Memoranda (O) Nos. 1-100 – War Cabinet and Chiefs of Staff Committee Memoranda – page 131
  5. National Archives – CAB 80. Memoranda (O) Nos. 1-100 – War Cabinet and Chiefs of Staff Committee Memoranda – page 331
  6. War Cabinet Chiefs of Staff Committee 19th February 1943 – National Archives Reference – CAB 79/59/24
  7. War Cabinet Chiefs of Staff Committee 1st March 1943 – National Archives Reference – CAB 79/59/31

Author: Nick Le Huray 🇬🇬

Guernsey based amateur historian. Interested in the Occupation of the Channel Islands and wider Second World War history.

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