When Panasonic announced the Lumix CM1 during its Photokina press conference earlier this week, we weren't sure what to make of it. Was it a slightly chunky smartphone with an upgraded rear camera sensor, or was it a seriously thin premium compact camera that also happens to have a SIM card slot?

After speaking to the people that helped bring it to life and spending some quality time with one earlier today, we feel we're ready to answer that question - and bring you some in-depth first impressions.

Crucially, the CM1 doesn't say Panasonic anywhere on the front or back of the device; it's a Lumix product, meaning the camera takes precedent over all smartphone features. With a faux leather finish and real metal around the frame, it fits right in with the rest of the Lumix camera range and feels every bit the premium device. It wouldn't appear out of place next to a Vertu smartphone , either, suggesting it has the looks to back up the high price - roughly €900 when it launches in select markets later this year.

At 21mm thick it's a lot more substantial in the hand than your average smartphone, but this makes for a much more natural shooting position. A physical shutter button with half-way focus and dedicated "camera release" switch which immediately opens the camera app and slides satisfyingly back into place add to the "camera first" impression.

You don't get an optical zoom like you do on Samsung's Galaxy K Zoom, but the Leica-built, f/2.8 lens should be able to add depth blur and bokeh effects to your photos. The manual control ring around the lens, a first for this kind of product, lets you adjust digital zoom, shutter speed, ISO and white balance, while the camera app lets you adjust focus and metering modes and even shoot in RAW. There's a wide selection of shooting modes, including PASM and scene selection.

Unfortunately we weren't able to take our sample snaps away with us after of brief hands-on, so it's impossible to give a final verdict on image quality. Crucially, it needs to outperform existing smartphones significantly in order to justify the price and added bulk, but the 20-megapixel, 1in sensor is much larger than anything currently on the market, with more than five times the surface area of a Galaxy S5 , so should easily have the edge in terms of detail.

Sample photos did look excellent on the 4.7in, Full HD LCD display. It might not be up there with the QHD screens found on the LG G3 or Samsung's Galaxy Note 4 , but the 1,920x1,080 resolution panel still looked pin-sharp, bright and colourful. Viewing angles were excellent indoors under bright lights, but it remains to be seen how it copes outdoors in direct sunlight.

Unlike other hybrid smartphone/camera devices we've tried in the past, the CM1 is incredibly snappy. It jumps into Panasonic's custom camera app, which uses the Venus picture engine found in the recently-announced LX100 premium compact, with minimal delay, then throws you straight back into Android. Panasonic hasn't bogged down Google's operating system with custom skins or apps, and with a Qualcomm Snapdragon 801 quad-core CPU running at 2.3GHz providing the power, Android 4.4 KitKat should be able to handle anything you can throw at it.

The CM1 can shoot video at up to 4K resolutions, but only at 15 frames per second. That's because the camera is using the Venus image processor rather than the Qualcomm chip that powers the Android operating system - we would have liked to see the option for 30p recording using the Qualcomm CPU.

It has just about everything else you'd expect from a modern high-end smartphone, including Wi-Fi, 4G LTE, Bluetooth and NFC connectivity, 16GB of on-board storage, microSD card support for adding up to 128GB of external space, and full access to the Google Play store. The 2600mAh battery is far larger than the kind you'd usually find in a compact camera, but it remains to be seen how it will last as a daily use smartphone.

UPDATE 24/11/14 - confirmed for UK launch, price and store locations below

Although a UK launch wasn't planned at launch, the company changed its mind following positive customer feedback, and will be bringing a small number of the phone/camera hybrids to Britain on the 1st of December. You'll have to head to one of only seven physical stores and fill out a small questionnaire in order to secure your device, and even then it's a fist come, first served deal, but we're expecting the CM1 allocation to have been snapped up by the end of launch day.

Panasonic expects the CM1 to cost roughly €899 when it launches in France and Germany (in limited numbers) towards the end of the year - that works out to roughly £700 before VAT. With taxes, it will cost £799.99 here in the UK. That might sound expensive for a smartphone, but is it really? Canon's recently announced £580 Powershot G7 X, which also has a 1in sensor, is almost three times as thick and can only shoot photos or video; the CM1 doubles as a fully-fledged Android smartphone, and a good one at that. However, many may find it hard to treat the smartphone part of the device as a secondary aspect, given how much our lives now revolve around their use.

We think a similar camera, still powered by Android but without any mobile connectivity, would perhaps find a wider audience - it would still slip in your pocket, and although you'd need to connect to Wi-Fi to share your photos the price should be significantly lower. When Panasonic is confident it has tested the waters with the CM1, it will be interesting to see where it takes the concept next.

We'd happily ditch our thinner smartphone for a significantly better camera that can also take calls and check Facebook, and can't wait to give it a full review.