Paragraph 25 of L26 Health and Safety (Display Screen Equipment) Regs: 'However, with the merging of information and communication technologies, small screens are increasingly used for a wider range of purposes. Examples are mobile phones and personal organisers that can be used to compose and edit text, view images or connect to the Internet. Any prolonged use of such devices for work purposes will be subject to the DSE Regulations and the circumstances of such cases will need to be individually assessed. It cannot be assumed that such devices, having much of the functionality of full-sized DSE, are excluded because their screens are ‘small’'

The test relates to "prolonged use" and paragraph 25 of L26 is the reference. IMHO, asking people to use these devices for prolonged periods is just plain wrong. (signs off humming the top ten hit by the Move "Goodbye Blackberry Way..............")