As distinct from the printed propaganda, the P.W.E. headquarters having, in 1942, moved to Bush House, the Executive still held possession of the Riding School at Woburn Abbey and here selected staff administered the small clandestine broadcasting teams, the Research Units. These operated from a number of houses in the immediate area and Peter Eckersley was the consultant radio engineer, both to the Government and the associated secret agencies.

P.W.E. policy defined that each R.U. should believe itself unique and thereby not only enjoy the British facilities but also decreed that there should be an individual status for each station, so as to remain untainted by the ideas of others. Staff of the different R.U.s were never allowed to meet and the cars transporting them made use of a complicated series of shuttles, to ensure that their paths never crossed. Even so the system was not infallible and at least on one occasion broadcasters of a certain nationality overheard broadcasters of another in adjoining studios!

Also contravening the secrecy, despite the governments in exile not being told about the black broadcast activities, the Norwegian delegation nevertheless found out and then demanded full control. Being against the will of P.W.E., this provoked a stiff response from the Foreign Office, which soon caused them to fall into line! Each broadcast team would normally consist of four members, under a British housemaster. He supplied their material, vetted the scripts and ensured that only the authorised versions were recorded. The recordings were made in studios at Wavendon Towers and on July 25th., 1942, in the company of Harold Robin and Richard Gambier Parry a group of Americans were shown around a studio and control room, where they heard a playback.

Live broadcasts could sometimes be made but these required special permission and only took place in the presence of the Regional Director, whose territory was involved. Made by varying the groove width, rather than the 'hill and dale' technique, sometimes the records suffered 'needle jumping', which  betrayed the impression that the recordings were live, whilst for all broadcasts, strict security ensured that the entire output was independently monitored. The broadcasts were recorded onto glass based discs at Simpsons  and although the R.U.s were repeatedly asked not to make their records longer than 12 1/2 minutes they continued to do so with the result that the content could not be accommodated if they ran to 13 1/2 or 14 1/2 minutes and had to be cut off.

The output of the R.U.s was indeed prolific and by the end of January, 1942, some 2 tons (3000) records had been made.From Wavendon Towers the discs were then taken by car to the transmitting stations at Potsgrove and Gawcott. The cars were invariably black Hillman Minxes with the drivers dressed in civilian clothes. At the radio stations they were only allowed into the entrance and never into the transmitter room. Likewise, at 'Simpsons' they were never allowed further than the inner doors. As for their accommodation arrangements, on December 12th., 1941, Harold Robin said it had been proposed to roof in the garage yard and include a chauffeurs room and for additional facilities on Boxing Day, Gambier Parry ordered a hut for the Simpsons courtyard. For their meals, in the early new year it was suggested that the chauffeurs could eat at a local pub although at the end of January the transport chauffeurs, Weston, Vining and Newbury, suggested that they be paid an extra sum to dine at home in the village but in the event they were offered, from the following Saturday, an extra accommodation allowance of 5 shillings a week for lunches out. Initially Newbury was told and he would then discuss it with the others.

Also in the Transport Department, moves were afoot to delegate other duties for they asked if the Despatch Round could call and deliver the laundry from the outlying houses, since otherwise Transport had to send a van especially. In any event, from April 10th. the pay for the drivers was increased to £4 5s 0d. As for the vehicles, predominantly black Hillman Minxes, two of the registrations were CPW 49 and FYP 563. Relations with some of the R.U.s teams that they ferried could sometimes be strained as on August 1st., 1942, when Newbury complained of a driver's treatment by G3. The team had arrived 13 minutes late at Simpsons and when asked to explain by Gregory they said their car, driven by Vining, had arrived late at The Rookery. For his part, Vining said that he had been kept waiting for 10 minutes and he had even asked Delmer to hurry them up -----'That there Corporal's a liar and I'm not going to carry the can after two years -----'! A full report of the incident was eventually written and Delmer agreed to buck his team up. He then asked for the drivers to report their arrival, saying that G3 hadn't known Vining had arrived.

Amongst other vexations, on March 6th., 1942, the question of the Dawn Edge team going to Simpsons alone was reviewed. By the resulting decision it was agreed that if no one was available to accompany them, then they must be confined to the car en route 'and not be allowed to wander along the roads'. Amongst other annoyances Crossman, housemaster for Dawn Edge, never used the codeword but always referred to Simpsons as Wavendon Towers. In August, 1942, Mallett joined the team of R.U. drivers but sometimes other arrangements for chauffeuring were made. On 18th. April, 1942, Leeper and Kirkpatrick amongst others were scheduled to be picked up from the Old Rectory and then taken to Marylands, before continuing on to Simpsons. The drivers were informed but Leeper decided he would instead take the party in his Rolls Royce.

For the regular drivers, in April, 1942, it was arranged with the Chief Constable of Bedfordshire, at Shire Hall, that they should be given top priority if stopped. They would give their names and the registration of the vehicle but they were not to be detained.

The first R.U.s began in May, 1940. On November 21st., 1941, the new G5 station was discussed at length at The Rookery and the following day it was decided to cancel Libya as the target and instead redirect the programme to the Eastern Front. By December 25th. the station was still not ready. One team member was still in America but he could arrive at any time 'as he he is to come by bomber'! Apart from the scripts and the translations for the R.U.s other factors had also to be considered. From midnight on March 9th. unoccupied France put it's clocks forward an hour in line with occupied France and all the French R.U.s were duly informed.For their own listeners, the D.N.B., when appropriate, would put messages out to the effect that German Time was being changed to German Winter Time and when intercepted by the Milton Bryan Hellscreiber, this was conveyed to all the R.U.s to be implemented, except that the Bulgarian stations got in a muddle.

Accommodation for the teams was made in various large houses around the district and on January 24th., 1942, the French teams, F1 and F2 were moved to The Mount, Aspley Heath. On November 12th., 1943, Sefton Delmer and Air Commodore Blandy confirmed that G9 would be radiated daily between 2000 2300 B.S.T. on 83.2K/Cs via Asidistra. Transmissions would then continue until the last broadcast at 0800 hours on May 1st., 1945. By the end of 1942 transmissions were being made to 12 countries. From 4 transmitters, 23 stations were broadcasting by 1943 with the propaganda personnel transported to and fro by buses with darkened windows. First transmitting in 15th., September, 1942, one R.U. pretended to be in Germany run by Father Andreas, a bearded refugee German Catholic priest. The station, which continued until the end of the war, emphasised the impossibility of serving both Christ and Hitler.

The Wehrmachtsender R.U. picked up D.N.B. broadcasts on the Hellschreiber and was therefore able to transmit current news items even before they appeared in the press. Most items were true, with a few false trails thrown in. Modelled on the genuine German Wehrmachtsenders, the station even recorded and played back their own music programmes! Under an agreement with General Sikorski, one German R.U. transmitted news intended for Polish agents in Poland and Germany. With this information they would then feed the clandestine pseudo German newspapers.

Of the more bizarre intentions, on March 9th., 1942, Delmer announced that he wanted an 'Occult' station, G6, to start by the end of the week and he asked Robin to allocate a frequency and arrange a recording session.In 1942 B.B.C. German programmes included 'Aus der Freien Welf', which carried the otherwise forbidden hot jazz and swing. Introduced by Spike Hughes, at first the format took the form of gramaphone record programmes, interspersed with news and short talks but live dance bands were later introduced with Sefton Delmer as one of the commentators. In the style of Luxembourg the station carried songs performed by Lucia Mannheim, the wife of Marius Goring, who in Autumn, 1941, became the head of features of the programme.

By December, 1942, amongst the many stations were two French R.U.s. Radio Inconnue broadcast abuse to Germans and quislings and first transmitted on October 8th., 1942, Radio Patrie, as a joint P.W.E./S.O.E. venture, provided a direct link with organised French Resistance. This R.U. closed on May 9th., 1943, to be replaced by a new black station, Honneur et Patrie, which relayed all the orders and directives of the Consell de Resistance in London. Belgium operated two stations, one French and one Flemish which P.W.E. ran in close co-operation with the Belgium Surete, whilst the Dutch had a single station, associated with the Dutch government. As for the total results of the black broadcasters, only under the direction of Sefton Delmer did the whole endeavour become really effective, operating from the purpose built transmission centre at Milton Bryan, from 1943.