A bus has been touring round Barcelona during this year's Mobile World Congress trying to get locals to break a mobile phone.

Sonim Technologies claims that its XP1 is the world's most robust handset and meets the military IP-54 specification for toughness, water-proofing and dust-proofing. The phones have been hit, stamped on and driven over, but still work.

Joakim Wiklund, co-founder of Sonim Technologies, said: "Research commissioned by us indicated that 70 per cent of outdoor workers refrain from using their phones in the workplace because it might break.

"Some 40 per cent have broken their mobile phone in the past year, and common reasons are damage from humidity, dropping and crushing. We aim to provide a solution to this problem."

The phone is sold by Vodafone in the UK, and construction firm JCB has bought the UK rights to sell the handset branded with its disctinctive yellow and black colours. The JCB model was launched last year by Peter Jones of the BBC's Dragons' Den.

Sonim said that professional users are buying the phone for use in tough environments, but that consumers are also choosing the handset.

Hikers and trekkers are a large market, as are parents looking for a phone that children cannot break.