In the summer of 1940, following the evacuation of Dunkirk, vast numbers of pillboxes were built to counter a possible invasion from Nazi occupied Europe.
The threat receded with the invasion of the Soviet Union in June 1941. The timescale was thus quite short, but due to changes of plan, the interpretation of the existing or known pillboxes is somewhat speculative.
The work began under General Sir Edmund Ironside. His forces were under-trained, ill equipped and could not be deployed in the field. A plan relying on static defence lines was his only option.
It consisted of a "coastal crust", with inland areas divided into zones by means of stop-lines.
Some units, particularly those with tanks, were kept as a mobile attack force in the event of a full-scale invasion.
Unlike the Maginot and Siegfried lines, stop-lines were essentially natural features such as rivers, reinforced with pillboxes, etc.
In the event of a landing, the nearest stop-lines would be manned by infantry or the Home Guard, who would delay the enemy until the mobile reserve arrived with heavy weapons.
Most of the national or 'GHQ' lines were in the south. A north-south line ran from Essex via York to Edinburgh. Linked to this were seven east-west lines, including three in Northumberland, on the rivers Tyne, Wansbeck and Coquet.
The plan was quickly modified. An order of July 9 stated that: “Main crossings... will be defended by putting them, or the towns or villages containing them, into a system of all-round defence.”
Despite this, Ironside’s plan drew criticism from Generals Montgomery and Brooke, and the RAF complained that the enemy would capture the airfields before the mobile column could get there. It was also felt that the troops should be being trained, not spending time building pillboxes.
It’s hard to say how justified this was. Local author Stephen Lewins, in The Northumberland Beehive Pillbox (on the Pillbox Study Group website), writing about Thropton, says: “There are a number of ‘Beehive’ pillboxes in the area all of similar construction. There were many troops camped at Thropton who could possibly have been the builders.”
If so, the same was probably true in this area.
On July 19, 1940, after only two months in post, Ironside was replaced by Brooke. Both men were later promoted to Field Marshal and were raised to the peerage as Baron Ironside and Viscount Alanbrooke respectively.
Alanbrooke had seen the effect of the German blitzkrieg in France, with ground forces protected by air cover moving quickly along main lines of communication. Superficially, his strategy was the same as Ironside’s. But the coast was more lightly defended, with better and stronger mobile columns.
Static defence along stop-lines was replaced by well fortified nodal points, such as towns and bridges. As it happened, many pillboxes were equally suited to either plan.
You can’t make sense of a pillbox in isolation. It only ever existed as part of a strategic pattern.
On the Wansbeck stop-line, the main obstacles were the river and its towering banks, reinforced with pillboxes and other works.
At Mitford, both bridges were covered by pillboxes, at least one of which was of the beehive type, built with cement-filled sandbags.
They no longer exist, but a lozenge pillbox survives near the castle. It is well set back so as to cover a wide area of low-lying ground. Another one similarly stands about half-a-mile to the north east.
All these were clearly part of the Wansbeck line. But there are two more, both lozenges, on St Leonards Road, going north to Fairmoor.
One is at Spital Hill. Here, unlike the Cottingwood pillbox that we saw recently, you entered the porch standing up and the hole you crawled through is at the far end.
The other is half-a-mile further, in a wood. It is heavily overgrown, but is interesting for having four loopholes on the porch side: two in the main wall, one in the external blast wall, and one overlooking the entrance.
These two pillboxes are not part of a stop-line. Like the one at Cottingwood, they cover a minor north-south route that an invading enemy could have used as an alternative to the A1.
We see the same evidence of alternative strategies at Bothal. Below the castle is a ford with stepping stones. On the far side are the anti-tank cylinders that once formed a barrier across it.
Further upstream, at Shadfen Bridge, is a beehive pillbox with cement rendering. Our picture shows the interior, taken through one of the embrasures. What looks like well-coursed masonry is, in fact, sandbags.
Both features clearly belong to the Wansbeck stop-line, but they can equally be seen as covering minor north-south routes. This is confirmed by the embrasure in a garden wall opposite Bothal church.
Note: All pillboxes are more or less dangerous. Don’t go inside, and don't go on private land unless you have permission.