Select Committee on Public Accounts Minutes of Evidence

Supplementary memorandum submitted by the BBC

  Question 102 (Mr Richard Bacon): A note would be very interesting and perhaps some photographs. Is it possible to get some photographs showing the bulb not illuminated and another one once it had been fixed and a time line of how long it took and how much the total cost was? Can you include all of those

  The failure mentioned by Mr Bacon concerned the malfunction of a large neon tube in the form of a letter which represents the BBC logo on the side of Television Centre. These tubes are specially made to ensure the size and font represents the BBC brand.


  The cost of the repair was £4,548.52 which included the following:

    —    £950 for the hire of scaffold for one day which provided the access platform and included the cost of a driver;

    —    £2,832 for the cost of materials;

    —    £388.32 in Labour charges (£32.36 per hour for 12 hours); and

    —    £378.20 10% agreed contractor uplift.

  Specialist equipment was required to reach the sign due to the lower ground floor roof not being designed to take the loading of scaffolding, the height of the sign which is over 20 metres and the sloping road on which the access platform needed to be set. This equipment is not available from the plant that resides at the BBC and thus had to be hired in from a specialist supplier.


  We do not have an exact date of the breakdown on our records as they are with our former supplier. However the problem was noted on 15 April 2006. Land Securities Trillium (LST), our incumbent supplier at the time, acted immediately by assessing the situation and procuring the specialist part and access equipment.

  LST then made the necessary arrangements to close the area off to complete the works. This included negotiation with the key stakeholders (BBC Resources and BBC News) and the submission of health and safety assessments and method statements to the BBC for verification.

  The job was closed down by the end of May although the repair itself took one day on site.

  Since the work was completed in May 2006 there have been no further reports of failure.

  We regret that no suitable photographs are available.

Question 170 (Mr Philip Dunne): Could I ask what the actual targets are for coverage across the UK, taking into account all the contracts the BBC has?


  The coverage of the BBC's transmission and distribution platforms is estimated to be as set out below:
Population served
    Network FM (Radio 1-4)99.0%
    BBC local radio FM91.0%
    BBC Radio Scotland FM98.5%
    BBC Radio nan Gaidheal FM93.8%
    BBC Radio Wales FM62%
    BBC Radio Cymru FM94.8%
    BBC Radio Ulster FM97.9%
    BBC Radio Five Live MW98%
    BBC Radio 4 LW/MW95%
  Digital Terrestrial Television (DTT) 82%
  DAB Digital Radio—UK multiplex 85%
  Digital Satellite96-98%

  These figures should be read in conjunction with the notes below:

  (1)  All figures are quoted as the percentage of the population served by the platform to a degree of accuracy commensurate with the method of calculation. The base population information is not necessarily the same for each platform, as the estimates have been made over an extended period of time.

  (2)  All figures are quoted for a defined minimum technical level of reception, which is usually expressed as a specified field-strength at a point at a certain height above the ground which is corrected so as to give reception free from interference for a particular proportion of the time when using an appropriate receiving antenna. These assumptions (for example, the height above the ground, the performance of the receiving system, the percentage of time for which services are protected) are not common between the platforms. However, the assumptions are made for each platform to represent a "good" reception standard. The percentage of the population making use of signals and services at levels below this technical minimum is not included in these estimates.

  (3)  In respect of analogue television, the figure quoted is based on computer predictions of coverage from the existing transmitting station network incorporating an assessment of the possible interference from continental transmissions. The figure quoted represents the proportion of the population who can receive "good" reception of the four main analogue terrestrial services: the figure for each of the BBC services considered separately is up to one percent higher.

  (4)  In respect of analogue network FM radio, the figure quoted has been calculated by subtracting the population in known deficiency areas (ie those areas not receiving adequate signal strength) from the total population of the country. As the deficiency areas are known with a high degree of reliability, this figure is believed to be accurate.

  (5)  In respect of BBC Radio Five Live MW and BBC Radio Four LW/MW, the figures quoted have been based on counts of population within the measured service-areas of the individual transmitters. The figure quoted is for general day-time coverage; the reliable, interference-free coverage of most transmitters after dark is substantially smaller than that during the day.

  (6)  The BBC does not possess accurate coverage figures for the medium-wave transmitters carrying its regional and local radio services. In the case of BBC Radio Wales, medium-wave coverage is vital and, when combined with the FM coverage, extends the service-area of this station to something comparable to that enjoyed by the other regional services in their respective regions.

  (7)  In respect of BBC local radio, the figure quoted is the sum of the predicted coverage of each FM transmitter carrying a BBC local radio station in England, adjusted so as to eliminate any double-counting of population served by two local radio stations. The same is true for the figures quoted for BBC regional radio. Editorial (and, with regard to regional radio stations, national) boundaries are thus ignored. The figure does not include the (relatively small) contribution of a number of small "filler" transmitters added recently to the English local radio network.

  (8)  In respect of digital terrestrial television, the figure quoted is the predicted proportion of the population able to receive both of the BBC's multiplexes together from a single transmitter. The BBC estimates that around 73% of the population can receive all of the six multiplexes that together comprise the Freeview service.

  (9)  In respect of DAB digital radio, the figure quoted is for the coverage of the BBC's own national DAB multiplex (which carries digital versions of the network radio services, BBC 6 Music etc) and not for the coverage of various BBC local and regional radio stations on DAB. The coverage of these latter multiplexes is set and regulated by Ofcom. Uniquely amongst the coverage figures presented in this note, the figures for DAB are quoted for mobile reception out-of-doors and at 1.5 metres above ground height.

  (10)  In respect of digital satellite coverage, the figure quoted is from research work undertaken by the Independent Television Commission and represents the estimated proportion of households in the UK which could receive the Astra 2A satellite signal by erecting a dish on the exterior of the house.

  (11)  Ofcom estimate that in Q2/06 there were 2,843,471 subscribers to digital cable services and a further 530,554 subscribers to analogue cable services in the UK. As the BBC has carriage agreements with all cable television providers, all subscribers are able to receive BBC services. Most will also be served by either analogue television or DTT.


  As a broadcaster dependent on a number of external parties and companies for the distribution of its many services on many different platforms, the BBC cannot hold any single contractor to account for the BBC's performance in terms of an end-to-end system availability for an individual viewer or listener. Indeed, as parts of the system from studio to listener are common for each platform—and some are common between some platforms but not all—the transmission of any BBC service across all of the platforms it is carried on touches upon many contracts and involves many parties.

  Accordingly, the BBC measures availability separately in each of its transmission and distribution contracts considering individually the elements of the process for which each contractor is responsible. In setting availability targets, there are several fundamental principles:


  Some faults which occur are not the responsibility or the fault of the service provider, such as those faults which are caused by extreme weather conditions or propagation conditions or a failure on the part of the BBC. All contracts therefore contain a list of circumstances under which the service provider is not held "accountable": the precise nature of this list differs from contract to contract depending on circumstances.

Planned work

  In the case of systems which are not fully redundant or where their design or health and safety dictates, the service provider will need to undertake some planned work and maintenance which may require the shut down of the service. For example, work on antennas mounted on masts and towers often requires a temporary break in service in order that personnel can work in safe radio-frequency levels. Typically, this sort of planned work—which can, to some extent, be scheduled by the BBC—is deemed to be non-accountable.

Time weighting

  Faults which affect services at times of peak viewing and listening are of more impact on the audience than at other times. Accordingly, transmission contracts typically have a weighting scheme which up-weights peak time and down-weights out-of-peak. For example, under the analogue transmission contract, a minute at 7.30 pm on a weekday evening is weighted four times greater than a minute at 3.30 am on a weekend morning.

Degradation weighting

  Not all faults are as severe as the breakdown of pictures or sound: for example, the failure of Ceefax or NICAM stereo sound transmissions for analogue television; or the failure of the dynamic RDS service on FM radio. Therefore, transmission contracts typically apply a weighting factor corresponding to the perceived annoyance of the fault relative to a complete breakdown. For example, under the analogue transmission agreement, a fault causing an FM service to be radiated in mono (rather than stereo) sound is weighted at one-tenth of a fault causing breakdown.


  Generally, all transmission contracts consider the average performance of a transmitter or a network, typically averaged on a monthly or six monthly basis. This acknowledges that transmission equipment is typically highly reliable but when it fails, it fails for brief, catastrophic periods. Averaging over a suitable period thus better reflects the generally high availability of the service.

  The currency which is used in the BBC's transmission and distribution contracts is, therefore, typically "average, weighted, accountable availability" with the terms upon which each is calculated set out in the contract itself. The level at which the availability targets are set and the methods used for their calculation are done so as part of the process of negotiating each new contract and should reflect both the BBC's expectations for the service and the design of the infrastructure to be put into place. There is inevitably a trade-off to be made at some point between the target contractual availability of a service (or part of a service) and the price to be paid for that service. It is the BBC's experience that at the levels of very high availability, further improvements—in order to gain further tenths or hundredths of contractual availability—are disproportionately expensive.

  The figures quoted below are contractual availability under the transmission and distribution contracts and do not consider the contribution of faults which occur earlier in the process, i.e. in the play-out chain.

  For analogue services, the BBC's target availability under its contracts with National Grid Wireless is as in the following table. Note that this covers from the receipt by National Grid Wireless of the signal (typically at a BBC studio centre) to transmission by the antenna at a station.
ServiceTarget average, weighted, accountable availability

Analogue Television99.9% Stations serving more than 100,000 population, calculated per station and averaged over six months.
99.8%All other stations, calculated per month.
Analogue Radio99.9% Certain priority stations, each serving a large population, calculated per station and averaged over six months.
99.8%All other stations, calculated per month.

  For digital services, the BBC holds contracts with National Grid Wireless for transmission of the DTT and DAB services; Siemens Business Services for coding and multiplexing of all DTT and digital satellite signals; Siemens and Arqiva for the uplinking of various multiplexes to the Astra satellite constellation; and SES Astra for the satellite capacity on-board the Astra fleet. The target availability for each is as in the table below, expressed for performance from the contractor's receipt of the signal to its hand-over to the next.

ServiceTarget average, weighted, accountable availability

DAB Digital Radio99.9%/99.85% (National Grid Wireless) Depending on station infrastructure design, calculated per station and averaged over six months.
DTT Coding and Multiplexing99.99% (Siemens Business Services) Calculated per emission multiplex, averaged over 12 months.
DTT transmission99.9% (National Grid Wireless) Calculated per station and averaged over a month.
DSAT Coding and Multiplexing99.99% (Siemens Business Services) Calculated per emission multiplex, averaged over 12 months.
DSAT Uplinking99.99% (Siemens Business Services/Arqiva) Calculated per multiplex uplinked, averaged over 12 months
DSAT Satellite Capacity(SES Astra) [6]

6   This data is commercially confidential. Back

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