Summary

The site of a Second World War QF P-series oil bombing decoy at Allhallows on the Hoo Peninsula, dating from 1940-41. Used to deflect wartime bombing raids from extensive oil storage installations located 2km to the south, on the Isle of Grain.

Source: Historic England

Details

PRINCIPAL ELEMENTS
The monument includes a complete QF P-series oil bombing decoy site in two separate areas of protection, which comprises the below ground structural remains of two circular oil rings, a pair of mirrored oil crescents, a small irregular shaped oil pool and connecting channels containing balancing lines with concrete sumps and other associated structures, evident as vegetation marks. The principal decoy features are located at TQ 8567 7736 (centre). The remains of two buildings including a reinforced concrete control building and generator building or store, with a surrounding earthwork bank, are located on an area of slightly higher ground, 300m to the west in a separate scheduled area at TQ 8534 7745 and TQ 8531 7748 respectively. The decoy site is situated to the east of Allhallows village on Allhallows Marshes at the eastern end of the Hoo Peninsula, Kent.

DESCRIPTION
The decoy site differs slightly from the standard layout for its type and has two circular rings approximately 15m and 20m in diameter, a pair of mirrored oil crescents approximately 20m in length and 5m in width, and a small irregular shaped oil pool, the below-ground concrete structures of which survive. The oil rings are contained within enclosures with a narrow ditch and bank or bund presumably to act as firebreaks. Oil sumps for each pond are located outside the enclosures linked to the pools by channels containing the electrical wires or oil balancing pipes. The outlines of the structures are highlighted by strong vegetation marks on aerial photographs indicating that the oil pool structures are present beneath the turf, their linings intact enough to retain water. The traces of a number of narrow, concrete-lined channels which probably contained the buried balancing lines and possibly the remote ignition wires can still be seen cutting across the site. Some of the piping and wires may survive within these channels. At least one of the external oil sumps for the oil rings at the northern edge of the site can be seen as an open square depression on the northern edge of the site.

The reinforced control building retains its flat roof and projecting blast walls which protected the main doorway. Levelled remains of earthen banks, built to provide additional blast protection extend around the building. Remains of an extant 30m long and less than 1m high narrow earthwork bank are built partly on the old sea wall, immediately north of the reinforced control building. The second building, a generator building or a store survives as a concrete floor with vestiges of the end walls and two parallel inner dividing walls remaining.

EXTENT OF SCHEDULING
The scheduling comprises two scheduled areas, the largest of which contains the principal decoy features and is defined by present field drain boundaries to the south, east and west and a modern track to the north which lies within the field boundary. It measures c400m north-south by c400m east-west. The second area, which includes the control buildings, is defined by a field boundary to the west, a track to the south and includes a section of the former sea wall bank to the east which appears to have been used as a protective feature. It measures c75m east-west by c75m north-south. The monument includes a 2m buffer for its support and preservation.

EXCLUSIONS
Fences and tracks are excluded from the scheduling although the ground beneath them is included. The surrounding land drains are also excluded from the scheduling.

Source: Historic England

Reasons for Scheduling

The site of the Second World War QF P-series oil bombing decoy at Allhallows is scheduled for the following principal reasons:

* Period: as one of eleven specialised QF (controlled fires) P-series (Petroleum Division) oil bombing decoy sites developed between 1940 and 1941 to deflect wartime bombing raids from extensive oil storage depots during the Second World War;

* Rarity: as a rare example of a near-complete OF P-series oil bombing decoy, one of only two of this type known to survive in England;

* Survival and diversity: a well-preserved, extant and fully legible bombing decoy of an unusual type, with all of its principal decoy features surviving above and below ground, including its control buildings;

* Documentation: the site is well-documented having been subject to research and aerial photographic survey, the bombing decoy is included on historic OS maps and records;

* Potential: there is a high potential for further archaeological remains associated with the oil pools, connecting channels and other principal decoy features. There is also potential for artefactual and waterlogged ecofactual remains.

Source: Historic England

Sources

Other
Carpenter et al, 2013, Hoo Peninsula Historic Landscape Project, Eh Research Report Series no 21-2013
Dobinson, C, 1996, C20th Fortifications in England Volume III, Bombing Decoys of WWII, CBA, York
Dobinson, C, 2000, Fields of Deception: Britain's Bombing Decoys of WWII, English Heritage
Small, F, 2014, Allhallows, Medway, Kent Second World War Oil QF Bombing Decoy, EH Research Report Series no 8-2014

Source: Historic England