The second-generation BMW 1-series will eventually evolve into six different body variants on two distinctly different platforms.

This variety will broaden the line-up against increased competition from the third-generation Audi A3, new Mercedes-Benz A-class and the Mk7 Volkswagen Golf — all due out next year.

Of most significance are two new front-wheel-drive models — a GT crossover and a small estate — due in 2014. They will pave the way for the third-generation 1-series range in 2018, which will see the bulk of body styles switching to a front-wheel drive set-up.

Read the full story on the new BMW 1-series

2011/12 - Five-door and three-door hatchesThe initial five-door and three-door 1-series hatchback models ride on rear-wheel drive (and optional four-wheel drive) underpinnings shared with the next-generation 3-series. The five-door model will launch in the UK in September and will be followed into showrooms by a three-door in spring 2012.

2013 - Coupe and CabrioletThe replacements for today’s two-door coupé and cabriolet models will also be rear-wheel drive. Significantly, they will renamed 2-series as part of a move to differentiate them from the 1-series hatchbacks.

The rear-drive 2-series models will differ from the 1-series hatchbacks by offering new turbocharged 3.0-litre, six-cylinder engines, with an optional seven-speed dual-clutch transmission. The 2-series will be aimed primarily at the US market. However, while a four-door saloon might sell well in the US and Asia, sources insist no such model is in the pipeline.

2014 - Front-drive GT Crossover and EstateIn the future, BMW plans to introduce a more practical five-door 1-series GT featuring a high roof and riding on a new front-wheel drive platform that will be shared with various Mini models. The GT is likely to preceed an estate version aimed at stealing sales from the popular Audi A3 Sportback.

2018/2019 - Third-gen 1-series goes front-wheel driveIt’s a long way off, but Munich planners intend to switch the bulk of 1-series to front-wheel drive for the third-gen model. The exceptions will be the coupé, cabrio and a new saloon, the first time a three-box four-door will feature in the 1-series line-up.

These models will stick with rear-wheel drive largely because the bulk of sales will be in the US, but also to allow convincing performance spin-offs. BMW’s new compact saloon will rival the Audi A3 saloon (previewed at the Geneva show in March), the new front-drive Mercedes CLC 4dr and VW Jetta.

See all the latest BMW reviews, news and video