The Ferrari Lancia D50 #4 was a Formula One car that competed in the 1956 British Grand Prix. The car was driven by Spanish driver Alfonso de Portago and British driver Peter Collins, and they finished in second and third places behind their Ferrari teammate Juan Manuel Fangio.

The Lancia D50 was a joint project between Italian car manufacturer Lancia and Enzo Ferrari's Scuderia Ferrari team. The car was powered by a 2.5-liter V8 engine and featured a tubular spaceframe chassis and a streamlined bodywork designed by engineer Vittorio Jano.

At the 1956 British Grand Prix, held at the Silverstone Circuit, Fangio took pole position in the Lancia D50 #2, with Collins in third and Portago in fourth on the grid. Fangio led the race from start to finish, while Collins and Portago battled for second place, with Collins eventually coming out on top. The Lancia-Ferrari team dominated the race, with the top four finishers all driving D50s.

Unfortunately, the Lancia D50 project was short-lived, as Lancia withdrew from Formula One at the end of the 1955 season, and Ferrari took over the remaining D50s. The car was eventually replaced by the Ferrari 801 in 1957.