Regular Pocket-linters will be no strangers to Modu. Indeed, we first saw the tiny mobile phone concept back in February 2009. However, the Israeli-built handset has finally made it to these shores, care of Purely Gadgets, so it's well-worth another, more intensive look.

The concept is certainly unique. Measuring just 72.1mm (H) x 37.6mm (W) x 7.8mm (D), Modu is purportedly the world's smallest mobile phone. It's even made it into the Guinness Book of Records. However, the tiny form factor has no buttons so, while you can use it as a fully-functioning handset, with an in-built mp3 player, you have to scroll through numbers just to dial out, or store all of your contacts in its database (via a PC) and hope you don't have to call anybody new.

That's where Modu jackets come in, and the name of the handset starts making sense.

Modu is so called because it is modular. It is designed to be slotted into a range of different jackets and devices, each of which add new functionality to the phone.

For example, when slotted into the Modu Night Jacket - the only one that has an in-built 3.2-megapixel camera - it becomes a camera phone. Each jacket comes with an on-board chip that adds features and/or changes the screen graphics.

Other jackets in the range include the Mini (small form factor), Speedy (which is, essentially, more robust for outdoor activities), Express (has a lanyard hole), Shiny (more business-like), and Sports, which comes with an arm band for running or the gym. They range in price from £29.99 up to £49.99.

The phone itself, as a stand alone product, costs £129.99 and comes in a variety of colours, including pink, blue, black, pearl (white) and metallic (silver).

Also available is a compatible photo frame for £79.99, which also has the ability to play video files stored on the Modu's 2GB internal memory. There's no way of expanding that, however, nor can the tiny handset play the videos on its own screen, only when hooked up to the frame. Naturally, it can also play music or a picture slideshow through the picture frame.

In use, the Modu is as simple as it gets. It's almost the absolute opposite of the modern smartphone. You have a menu and a four-directional choice of options. That's it. However, it's ideal for those who don't want complication in their lives. And you can be sure that it'll get reception no matter how you hold it.

Purely Gadgets is selling the Modu completely unlocked and is the exclusive distributor for the phone, at least for a year. And, according to the site's chief inspector, Andrew Tse, its popularity will grow as more people use one: "Once it catches on", he told Pocket-lint, "a lot of it will be word of mouth and social networking".

He also believes that it could be bought by customers who want a second, convenient phone: "I guess some [would] use it as a second phone", he said. "A lot of people are now using a second phone. Saturation is now more than 100 per cent, so some people are definitely using more than one phone".

There's only one thing that Pocket-lint was bemused by. Scattered everywhere at the launch were these tasty speaker/charge docks, which used a flat surface, such as a table, to amplify sound. However, Andrew told us that "the speaker system is only a promotional product, and is not available for sale at the moment". So, if you opt to plunge into the world of Modu, give Purely Gadgets a prod and demand that they carry the speaker set too. To be honest, it was our favourite part.