BMW has hatched plans for a new BMW 1-series badged rear-drive junior saloon that is being pitched as the spiritual successor to the E30-generation 3-series four-door.

The car will play an integral role in meeting BMW’s ambitious worldwide sales target of two million cars a year by 2020, and should become one of the firm’s best sellers in key saloon markets such as North America and China.

The new four-door will join an expanded 1-series line-up as a rival to the upcoming third-generation Audi A3 and Mercedes-Benz CLA compact saloons, as well as the established Volkswagen Jetta.

It could go on sale as early as 2015 and will undercut BMW’s perennial best-seller, the 3-series saloon, on price.

Before the four-door 1-series arrives, however, BMW will launch successors to today’s first-generation 1-series coupé and convertible, codenamed F22 and F23 respectively and due in 2014.  

Central among BMW’s decision to push ahead with a 1-series saloon are the ever-increasing dimensions of the 3-series saloon. Since its introduction in 1975, it has grown by 269mm in length, 210mm in width and 49mm in height, taking it into a higher market segment.

Using a rear-wheel drive platform that shares some key elements with the latest, sixth-generation 3-series should ensure a sporting drive for the 1-series saloon.

The decision to adopt this rear-drive layout comes despite the creation of a new front-drive platform to be shared with Mini. It will be used for a new 1-series GT model in 2013, a rival to the Mercedes-Benz B-class and next year’s third-generation Mini.

Four and six-cylinder engines will feature in the 1-series saloon line-up, while an all-electric version is also under consideration. Four-wheel drive will be an option.

Initially, the four-door 1-series will be built alongside hatchback, coupé and convertible models in Leipzig, Germany. In the longer term, it could also be built at BMW’s Shenyang plant in China and a new facility earmarked for Santa Catarina, Brazil.