The W76 variable-mu screened pentode was designed for intermediate frequency amplifiers in superhet type receivers. The W76 has a high impedance allowing for a high Q in the tuned anode circuit.
The Marconi brand label but also the Marconiphone company name. This suggests that M-OV made this for the consumer products arm - Marconiphone.
The outer cylindrical screen covers the internal structure.
Looking up from the base: the cylindrical anode can be seen within the outer screen. The coated cathode and wire grids can be seen. The control grid support is made of copper.
The wide glass tube envelope is 28 mm in diameter and excluding the IO Base pins the valve is 86 mm long.
References: Data-sheet, 3002, 1040 & 1043. Type W76 was first introduced in 1945. See also1945 adverts.
