Possible German invasion of Britain WWII: in-country procedures, personnel, emplacements?

[Mk_VII]

*Home Forces continued throughout the summer to be dogged by shortages of almost everything they needed to oppose an invader expected to achieve high standards of speed and hitting power. Big additions to his manpower did, however, enable General Ironside to reconsider his problems and evolve a new plan of defence. As he now saw it, his first aim must be to 'prevent the enemy from running riot and tearing the guts out of the country as had happened in France and Belgium. He concluded that, at all costs, his troops must be deployed in sufficient depth to ensure that any substantial German force that got ashore could be halted before it reached London or the industrial Midlands. At the same time they must be ready to intercept any reinforcements whose arrival the navy and air force were unable to prevent.

To achieve both aims in the circumstances existing in the summer would be very difficult. For the most part the troops at the Commander-in-Chief's disposal were not only ill-equipped; they also lacked mobility, and their training had not envisaged tasks of the wholeheartedly offensive character which German tactics now seemed likely to impose. There were nearly five hundred miles of beach on the South and East Coasts suitable for the landing of armoured fighting vehicles, and about a third of this expanse of coast was in the neighbourhood. where the invader could be most strongly supported by air power.6 At the same time, airborne troops might land a long way from the sea. In the absence of strong mobile forces deeply imbued with the offensive spirit, Ironside came to the conclusion that his best chance lay in combining his few mobile columns with static defences deployed over a wide area. The pivot of the new plan which he and his staff worked out in June was a G.H.Q. line of anti-tank obstacles covering London and the Midlands, supplemented by a series of command, corps and divisional stop-lines sited further forward.  The G.H.Q,. line, following natural obstacles such as waterways and steep inclines where they came to hand, ran from the neighbourhood of Richmond in Yorkshire to the Wash, and thence through Cambridge to the Thames at Canvey Island; south of the Thames it continued through Maidstone and Basingstoke to Bristol. Of the forward stop-lines, five ran across the Eastern Counties to check an advance from the vulnerable beaches about Lowestoft, either towards the Midlands or across the open uplands north of London. Three crossed Surrey, Kent and Sussex, barring the approaches to the capital from that direction. Generally the role of divisions in front of the G.H.Q. line was to exploit the forward stop-lines so as to confine, break up and delay an advance from the coast, thus giving time for the arrival of mobile forces from the G.H.Q,. Reserve. Accordingly, most of the 786 field guns available in the middle of June were sited near the coast to cover the most likely landing places, while conversely the better part of the 167 anti-tank guns which Ironside could muster were kept back in G.H.Q,. Reserve. To gain further time, beaches were mined and obstructed, roads leading inland were blocked, and stocks of incendiary grenades and 'sticky bombs' (for dealing at close quarters with armoured fighting vehicles) were provided at every guard-post. Auxiliary units were trained to work in the rear of an invader, harrying his advancing columns and cutting them off from supplies of water, food and petrol.

Manifestly these tactics, harassing rather than destructive as they clearly were, would be effective in the long run only if the mobile forces, when they did arrive, could deliver something like a killing punch. And here, unfortunately, Ironside was very weak. In the middle of June his general reserve included three of the better-equipped infantry divisions and the 1st Armoured Division. The last, having left behind in France 100 infantry, 163 cruiser and 354 light tanks, had returned to the United Kingdom with nine tanks all told; and its effective strength at the end of June consisted of 81 medium tanks which had reached it in recent weeks as an instalment of its new equipment. In addition the 2nd Armoured Division, now with 178 light tanks, had moved to a position between Northampton and Newmarket, whence it could strike, as best it might with limited resources, at the rear and flank of an invader pressing inland either from the East Anglian coast or from points north of the Wash. The infantry divisions remained in the area Northampton-North London-Aldershot, in order that they might advance as rapidly as possible by brigade groups to any threatened area. The number of tanks in the United Kingdom was, indeed, much greater than the total of the effective strengths returned by the two armoured divisions; but the fact remains that most of them were not considered fit or available for use by the only formations that could use them.

Among the more obvious weaknesses attending these arrangements were an insufficiency of anti-tank guns to support both the forward lines and the G.H.Q. line; a lack of local reserves, as distinct from the G.H.Q. Reserve; and a lamentable shortage of the armour needed to give counter-attacks by the mobile forces a good chance of success. The plan was designed to make the best of a bad job where the first two were concerned, by allotting preference to the main line of defence; but the third was radical and inescapable. With four armoured divisions in reserve the Commander-in-Chief would have felt that the country was reasonably secure; as it was he had, in his own words, 'less than half the equivalent of one complete division'*

B. Collier, The Defence Of The United Kingdom (1956)

HyperWar: The Defense of the United Kingdom

[Hypno-Toad]

@Mk_VII

A Blacker Bombard position beside the Great North Road defending the Brookman’s Park radio station http://www.fototime.com/98A331C27AC51E2/standard.jpg this is scarcely visible today in the hedgerow http://www.fototime.com/C41DC61421CFF26/standard.jpg it looked more obvious once I cleared the vegetation http://www.fototime.com/303A0FB3E395E26/standard.jpg

It’s funny how some of the stainless steel pintles remain shiny and new after all these years. I saw a pic of a bombard position on the coast that had been filled in and all that was visible was the pintle sticking out of the ground.

[lisiate]

Peter Fleming (brother of James Bond creator Ian) wrote a good book on Operation Sralion and the British preparations to defend against it back in the fifties. His verdict was that it would have been a fiasco.

[JessMagic]

@Mk_VII

The plan, such as it was, was heavily criticised even at the time for allowing large portions of Southern England to be overrun before the decisive land battle would be fought, and in hindsight probably would have spelt the doom of England.

Scotland would be okay though, right? That’s all that really matters.

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[Leo_Bloom]

@Elendil_s_Heir

David Lampe’s The Last Ditch is well worth a read. Planning for a British Resistance movement was surprisingly extensive, and quite a few preparations were made.

Here’s a Wiki article that may be of interest: Auxiliary Units - Wikipedia

Lottsa photos in recent magazine article.
A chilling zombie, this. /not snark

[DeptfordX]

This is still the best single site i’ve seen explaining the numerous reasons why Sea Lion is impossible to succeed.

https://www.philmasters.org.uk/SF/Sealion.htm

Tl.Dr. The Royal Navy exists and the Germans have no idea how hard doing a reverse D-Day is.

[bob_2]

@Little_Nemo

The government did make plans for fighting the Germans in Britain but these were mostly done for the purposes of keeping up public morale.

As you can see from the following posts, that was pretty far from the truth. In fact a great deal of it was totally secret.

If you try to imagine how the British people felt (propaganda had turned the Germans into child eating monsters) you might understand that there were a great many people, men and women, who were quite prepared to fight to the death to prevent Hitler from moving into Buck House. They had seen what happened in Belgium, Holland and France, and there were not about to let it happen here.

[Evan_Drake]

Although old, Norman Longmate’s If Britain Had Fallen is a classic.
Had it fallen it would have been no worse than for most of the other countries; and not so worse as it was for the USSR. ( Probably been worse if the USSR had overrun all of western europe including the British Isles. ) The claims that the nazis planned to send all the British males to the Continent always seemed a little overblown.
Although quite bad in the Channel Islands, there were few atrocities ( apart from the use of Russian slave labour( HiWi ) and a couple of concentration camps ( as usual malnutrition and casual brutal methods rather than planned murder ), and islanders settled into the routine as all occupied people do.

[PatrickLondon]

Oops

[Seren359]

There were extensive plans in place which were approved and supported by Churchill to use Mustard gas to prevent any invasion force from leaving the beaches.
Gas production facilities were available at Randle and Sutton Oak, and more were being brought on line in 1940.

While the Royal Air-force bomber command was not yet equipped with big modern bombers it had trained to deliver Mustard gas. Also the Army had specialised gas corps with weapons.

All the likely beaches had been mapped and amounts of gas required were planned.

Civilian casualties were seen as acceptable if the result was to repel an invasion force.

[Isilder]

@Mk_VII

The plan, such as it was, was heavily criticised even at the time for allowing large portions of Southern England to be overrun before the decisive land battle would be fought, and in hindsight probably would have spelt the doom of England.

OH ?

The idea was that operation sea lion requires air superiority.
Basically any ground invasion that went ahead without air superiority would surely allow time for the RAF to escape, and then the RAF would be totally free to menace the nazi’s on the ground and at sea. British ground forces would be surrounding the attack areas, and disrupted nazi’s would be easily dealt with.

Meanwhile the heavy divisions would be held up over on the continent, and then the Royal Navy would be returned from escort duty to prevent further channel crossings.

It would be like the Tet offensive in Vietnam … The communists drive a jeep through the USA embassy… great… So what ? What happens when it stops moving ? it gets hit. it was just a hard target to hit when it was uselessly moving around.

[bump]

@DeptfordX

Tl.Dr. The Royal Navy exists and the Germans have no idea how hard doing a reverse D-Day is.

Yeah, I always figured the primary British plan (as it has been for close to a thousand years) is to essentially rely on the Royal Navy to bear the brunt of the island’s defense, with the RAF playing a supporting role.

In other words, the Germans would have had to force an opposed landing against the entire strength of the Home Fleet and the RAF, and then manage to keep it supplied across the Channel against the further depredations of whatever other Royal Navy ships remained.

That’s a tall order indeed.

[Miss_Mapp]

There’s an interesting Time Team episode about the Shooter’s Hill defenses to protect London from invasion on YouTube.

[Leo_Bloom]

@Hypno-Toad

Hereis a link to a thread on the Axis history forum about the Germans’ intended use of paratroops in Operation Sealion. Specifically, the plans for the 7th Flieger division to take Lympne airfield on the southern English coast. It is an excellent thread where posters use google earth imagery to show where the proposed drop points were, the difficulties the terrain around the particular objective, the location of defence points, and the units that were stationed in the area. Of particular note, the paratroopers would have been dropping right into an area that had a unit specifically tasked with searching for and destroying paratroopers. The whole scenario is eerily similar to the later Market Garden debacle.

Good thread (re-read) and good website.

[Leo_Bloom]

nm

[Leo_Bloom]

It occurs to me, like all the what-ifs that the British military wrestled with then and which we analyze now, that the state of German intelligence, let alone strategic mindset in planning the invasion and achieving it initially, is as in all plans, ultimately unknowable.

I’m thinking of the opening of the 1973 Yom Kippur War, when Syrian troops found themselves on an open highway South, yet stood stock still fearing it was a trap, predicated on their complete assumed knowledge that Israel would never be so unprepared.

[Elendil_s_Heir]

C.S. Forester’s short story “If Hitler had invaded England” (found in his 1971 collection Gold from Crete) is the best fictional depiction I’ve read of a German invasion in WWII. Written as if a historical account some years later, it’s very detailed and realistic.

In the end?

The Germans can’t keep their troops adequately supplied (especially with gasoline), the Home Guard is surprisingly effective at sniping top German officers, the Royal Navy eventually cuts off the invasion force from the European mainland, and the British Army is able to mass its forces and decisively attack. After about three weeks or so IIRC, the invasion has utterly failed.

[Northern_Piper]

@bump

Yeah, I always figured the primary British plan (as it has been for close to a thousand years) is to essentially rely on the Royal Navy to bear the brunt of the island’s defense, with the RAF playing a supporting role.

As attributed to Lord St Vincent, First Lord of the Admiralty, during the Napoleonic invasion scare over a century earlier:

“My Lords, I do not say that the French cannot come. I only say they cannot come by sea.”