LONDON—British car production last year fell to its lowest since 1956, largely due to a global shortage of semiconductor chips that caused automakers to slow or shutter plants while waiting for parts, an industry group said on Thursday. The Society of Motor Manufacturers and Traders (SMMT) said production fell 6.7 percent from 2020 to 859,575 vehicles and was 34 percent below the pre-pandemic year 2019. “Overall, this was a deeply depressing year,” SMMT chief executive Mike Hawes told reporters. “The impact of the semiconductors really hit home hard in the last quarter of last year.” The SMMT said it expected the shortage to ease this year and cited independent production forecasts that British car output should increase 19.7 percent to above 1 million vehicles. The pandemic-fueled shortage of chips, used in everything from brake sensors and power steering to entertainment systems, has led automakers around the world to cut or …