The Southern Anti-diver balloon barrage deployed to the south of London was the last line of defence – it only got the “birds” that the AA guns and fighters missed. Nevertheless it made a substantial contribution in the battle against the V1, with 15% of bombs which entered the barrage area brought down. However, with the threat of land-launched flying bombs removed due to Allied advances, ADGB (Air Defence of Great Britain) considered that the future deployment of balloons was no longer necessary for the following reasons:
The scale of air-attack, from both enemy aircraft and air-launched flying bombs was considered to be so diminished as not to warrant a large deployment of balloons.
Balloons interfered with AA gun radar and hence the efficiency of the AA gun defences.
Balloons were specifically designed to counter the low level fighter-bomber attack, and as a result of Allied progress on the continent most vulnerable areas in the UK were now considered out of range of enemy fighter-bombers.
Balloons were no longer required in defence against enemy mine laying due to the ability of the enemy to lay “Oyster” mines from a high altitude.
The success enjoyed by both HAA and LAA against the flying bomb reduced considerably the need for a balloon barrage.
Above: part of the southern Anti-diver balloon barrage
It is fair to say that the scale of the air-launched V1 offensive from September 1944 onwards took ADGB by surprise and plans were drawn up for an Eastern Anti-diver barrage, to the north of London. The Chiefs of Staff still ordered the withdrawal of all balloon barrages in the UK on Sept 19th, with the exception of a temporary retention of the requirements necessary to fly the Eastern Anti-diver barrage. The plans were not to be implemented unless instructed, and in the end the barrage was never ordered.
The planned barrage was to consist of 829 balloons, each balloon flying an additional K.B.1A wire. A full reconnaissance of sites was carried out, including an inventory of work required to make them ready. On deployment being ordered, sites were to be made ready by crews and balloons inflated as soon as a suitable anchorage had been constructed, but not to be flown until ordered. Any works on site that could not be completed by crews was to be carried out by Airfield Construction personnel. Accommodation for balloon personnel was to be in American tentage, already held by balloon crews.
Hydrogen for the initial inflation of balloons was to be supplied as follows:
500 compressed trailers, Kidbrooke
300 compressed trailers, RAF Station, Cardington
267 Dodge Hydrogen Tenders, Fairlop
Subsequently, refill for cylinders would be available from Cardington, with factories at Cambridge, Bedford, Chelmsford and Wellingboro coming on line five to seven days after the order to deploy.