There are plenty of reasons to like this phone, aside from the appeal of its clever, slider mechanism.

Samsung's D410 is easily the most fun slider phone on the market. Size wise, it fits nicely in an average sized hand when shut. The phone's opening mechanism is easier to operate with one hand than anything else that Gizmogirl has tried. A little push on the sliding display and the phone automatically springs open. Most of the weight is in the bottom half of the phone and this helps to keep it nicely balanced in your hand, whether open or shut. Like clamshell phones, the D410 has the advantage of being compact when not in use but user friendly once open.

The most important feature of a phone is voice transmission and the D410 scores well. Once open, the earpiece and microphone sit just about where you want them. Building the top half of a slider or clamshell phone too thin gives you a rotten ear- piece. Not so the D410. Samsung has been careful to build both sections well. Thankfully, there are few surprises with the layout. Controls are split across the top and bottom halves of the phone, which gives you the option of using the phone either open or shut. Nice. When shut, we found ourselves holding the handset like a PDA and browsing menus and even the internet on the big screen: to take calls we slid it open to make it a better fit for chatting.

Samsung has added some useful options for switching on and off. To answer calls, there is the usual button to press but we set the phone to Active Slide. This meant that simply sliding the phone open answered calls. The volume button on the side is easy to use mid-call. Another favourite function was Silent Mode. If your phone starts ringing when you don't want it to, pressing the hash key switches the phone into Silent Mode. In place of the ringtone, the phone switches to vibrate. We prefer pushing a single key to silence a phone than having to open a menu, scroll and select an option. In fact, if you dislike everything polyphonic, then the vibration on this phone is strong enough to alert you to calls without using ringtones at all.

The display on the D410 is big; almost twice the size of standard mobiles. Samsung's thin film diode (TFD) screen manages 262,000 colours without noticeably draining the phone's battery ( a spare battery is included in the box). The big display means less scrolling, and is easier to use all round. With GPRS and WAP 1.21, it was possible to make some sense of the internet. For downloading games and content, the phone is Java enabled and is also compatible with POP3/IMAP4 email.

The display really comes into its own as a viewfinder when taking pictures with the VGA built in camera. The D410 uses the same rotating lens as Samsung's V200. It turns through 180 degrees for self-portraits. There are plenty of controls to master, like zoom, brightness levels and flip, as well as photo effects. A mutli-shot feature lets you take consecutive shots - 6, 9 or 15 - and then select the best to save. With video, you can capture 30 seconds of MPEG footage. The 10MB of built-in storage was sufficient in our tests: the D410 does not take memory cards so storage is fixed. We had to revert to the user manual for our camera tests to understand which button did what. The end results were very good, with more depth than we might expect from a mobile. As a handy camera phone for summer holidays, the D410 is recommended

Verdict

Samsung has the knack of adding interest to its phones without interfering with their functionality. It isn't pioneering with a sliding phone, the Siemens SL55 springs to mind straight away, but other models have been too small once shut to be of much use, or too big to be practical. Samsung has the dimensions - open or shut - just right. The big screen is a real plus, both for using the phone as a phone and for taking pictures. As well as big, it is also tough. After four weeks of heavy wear and tear, our screen looked like a shiny, new window that had just been cleaned. The case did not last so well and needs to be made more scratchproof. The D410 was exclusive to O2 during our test but it should be available on all networks by now.