Nokia's £13 phone with a battery that lasts a month - and other new handsets

Struggling Finnish smartphone maker Nokia has launched a budget mobile that costs less than a cheap rubber smartphone case - and has a battery that lasts one month per charge.

Aimed at developing economies and users in remote villages, the Nokia 105 will cost £13 and contain potentially life-saving features including a torch and FM radio.

It was one of several outlandish devices unveiled today at Barcelona's Mobile World Congress - a testing ground for new ideas in mobiles and smartphones.

The 'candybar' device marks the end of an era for Nokia - the 105's colour display means that the firm has now produced its last phone with a black and white screen.

[Related: Nokia unveils £150 smartphone]

One of four phones announced by Nokia at this year's Mobile World Congress, the company hopes the ultra-budget device will broaden its appeal and help it to establish a dominant position in both China and India.

Other companies aimed for Western consumers - and phones seem destined to get even bigger, and faster than ever.

Samsung Note 8.0 is described as 'the world's largest mobile phone' - it is an 8-inch tablet with full smartphone capabilities.

The size of an iPad mini, its combination of 3G and WiFi provides users with the option to make phone calls - as well as download the latest apps, games, movies and music.

The high-end device runs the latest Android software and is powered by a 1.6GHz quad-core processor which provides the power for advanced functionality such as the pen enabled screen.

The Note 8.0 is due to hit stores in the UK this spring.

[Related: Firefox takes on Apple and Android with its own phone software]

Japanese technology firm NEC has announced the world's first folding smartphone.

The innovative NEC Medias W has identical 4.3-inch touchscreen on the front and rear. The latter is mounted on a hinge and flips out - thus turning the device from a smartphone into a tablet.

While NEC's smartphones have failed to take off in the UK in recent years, the brand is still hugely popular in Japan, where this split-screen device is due be launched next month. A European prototype is currently in the pipeline.

Described by Huawei  as 'the world's fastest 4G smartphone', the Ascend P2 supports download speeds of 150 megabytes a second - enough to download 2,250MP3 tracks a minute.

While the Chinese firm is quick to point out that those figures are dependent on the user's network connection, the device also aims to tempt early adopters with a large, 4.7-inch HD touchscreen and a 13-megapixel camera.

The Ascend P2 is due to cost £350 and will go on sale in Europe in April.

A hugely popular smartphone brand in Asia and Africa, ZTE has launched the first smartphone based on Mozilla's Firefox operating system - a cheaper alternative to Google's Android.

With a basic suite of features, a positively Jurassic 3.2-megapixel camera and a low-resolution 3.5-inch touchscreen, the compact device is set to appeal to both emerging markets and those who need a second - or even third - phone.

Its success hangs entirely on whether Mozilla can drum up enough support from third-party app developers - though essentials such as mapping and email apps are already in place.

ZTE are set to launch the device in emerging economics this year - with a European and US release date scheduled for 2014.