BMW is set to take a huge risk by pressing ahead with the launch of the Progressive Activity Sedan (PAS) executive hatchback, a ‘5-series GT’.

The controversial BMW PAS is due to be unveiled in late 2009. One senior company source has told Autocar that the 5-series GT is “one of the bravest designs ever signed off by BMW”. But insiders describe the car as a ‘modern grand tourer with a luxury cabin and interior flexibility’.

The BMW PAS expected to be priced between the BMW 5-series and BMW 7-series and pitched at drivers who like a higher driving position but are not keen on full-scale SUVs.

One source has suggested that BMW is aware of an ageing population who now find conventional saloons’ seat positions too low for comfort.

Those who have seen the 5-series GT in the metal describe the BMW PAS as more of a ‘tall 7-series hatchback than a low-rise X6’.

The car is based on the latest version of BMW’s large rear-drive platform, first seen under the recently launched BMW 7-series.

Although the precise dimensions are not yet known, the PAS is slightly longer than a 5-series saloon and just shorter than a 7-series. It also rides slightly higher on its wheels than a normal road car.

The car’s overall height is pitched almost exactly between a 5-series and an X6, with higher than normal seating positions.

Insiders say this layout allows the PAS to offer the same rear leg room as a new long-wheelbase 7-series. Despite the sloping roof line, head room is said to be more than adequate.

The cabin is based on the same flowing theme revealed in the new Z4, with a wide centre console. Sources say front passengers get a “relaxing, semi-raised position”.

Although the 5-series GT gets a lower body similar to that of a saloon, the roof line and rear hatch are pure X6.

The car’s front end has more of a ‘nose cone’ look, rather like the recently cancelled CS concept. It also gets frameless doors, though there are no plans for a convertible spin-off.

The gently sloping roof line curves into an X6-style ‘fastback’ tailgate. The rear of the car is also said to be like the X6, with a lip at the base of the hatch window and a flat rear panel underneath it, between the rear light clusters.

Sources say the tailgate works in a similar way to the Skoda Superb’s, either as a hatch or with a saloon-style boot lid. But in the BMW it’s the upright rear panel that flips up, offering a letter box-shaped opening.

No definitive details have emerged about the 5-series GT’s technical specification, but it’s thought most European models will get a 3.0-litre turbodiesel engine and most US cars will use a 3.0-litre turbocharged petrol.