Weircliffe Model 7 bulk tape eraser used by the BBC.

Magnetic tape allowed for great flexibility of recording for the BBC and became the dominant format for audio and later video. Tape itself was expensive but costs could be reduced by erasing and reusing tape reels. Bulk erasers enable an entire tape to be cleared for reuse at once, over the more time consuming process of erasing at recording speed. The BBC regularly reused tapes and large volumes of recorded material was erased once its perceived value had been exhausted. The process declined for recorded programming from the late 1970s with an increased awareness of the value of archive preservation.

The Weircliffe Model 7 produces an electromagnetic field that erases, or degausses, the information stored on the magnetic tape. The unit has a capacity for up to 8 inch diameter tapes, which are loaded into a slot by pressing down on the blade on top of the unit. The tape is held over a core which produces the magnetic field. The unit produced considerable heat and the magnetic field could extend beyond the tape to erase data on nearby devices.