In the 1960s, Tungsram was a re-brander of tubes in the UK. They existed solely to distribute Mullard tubes to hifi. Later on Tungsram was independent and their tubes were made in Hungary.
"Tungsram is a Hungarian manufacturer of light bulbs and vacuum tubes since 1896. General Electric, in 1990, acquired majority share in one of Hungary's largest, oldest, and internationally most prestigious firms, the light-source manufacturer Tungsram. Over the past six years GE has invested $600 million in the venture and thoroughly restructured every aspect of its operations. It is the largest U.S. manufacturing investment in Central and Eastern Europe to date. It is now a subsidiary of General Electric and its name is used as a brand name only.
The company was awarded a patent for electric bulbs with a tungsten filament in 1903. Later in 1934, they also announced a patent for Imre Bródy's electric bulb filled with krypton. Both provided a longer lifetime for electric bulbs. The firm produced telephone apparatuses, wires, and telephone switchboards since the establishment of the company. Since the WW1, the mass production of radio tubes began, which became the most profitable branch of the company.
The name Tungsram is a portmanteau of "tungsten" /ˈtʌŋstən/ and "wolfram" /ˈwʊlfrəm/ (as tungsten, the metal used for making the filaments, is known in Hungarian, German and many other languages). British Tungsram Radio Works was subsidiary of the Hungarian Tungsram in pre-war days."
The Tungsram History - 1896-1945, book scan in PDF, from mek.oszk.hu.