Road Vehicles (Construction and Use) Regulations 1986 Rule 110 seems to give rise to such problems. Reg. 110(1) states - "No person shall drive a motor vehicle on a road if he is using (a) a hand-held mobile telephone; or (b)..
For present purposes (b) is not relevant.
The Regulations do not contain a definition of "using". It is clear enough that if the driver is making or receiving a call with the phone in his hand then that is "using." That must be so on any view of the meaning of the word "using" though such "using" to make an emergency call (112 or 999) would not be an offence where Reg. 110(5) applies.
Reg. 110(6) states - "(a) a mobile telephone or other device is to be treated as hand-held if it is, or must be, held at some point during the course of making or receiving a call or performing any other interactive communication function ..." That seems to be a fairly common-sense description of what is meant by "hand-held".
If a driver merely picks up a mobile telephone but is not making a call or texting is that to be construed as "using"? It could be argued that this was "using" given that the "mischief" at which Reg. 110 is aimed is that of drivers having only one hand on the vehicle steering wheel and thereby not having proper control. A potentially dangerous state of affairs. However, in one Scottish case it was held by a Justice of the Peace that this was not "using". See Daily Express 26th April 2008. [Such a case, whilst interesting, would not constitute a legal precedent]. If that view was right then it would be probably necessary for the prosecution to prove that the defendant was engaged in an actual communication and that would make the offence significantly harder to prove.
The word "using" is an ordinary word of the English language. Ordinary words are normally to be given their everyday (ordinary) meaning. Interestingly, it is almost impossible to define or describe "using" without including either the word "use" or "using" in the definition ! Thus, "using" would normally be taken to mean that the device was being operated for the purpose (or one of the purposes) for which the device exists (i.e. to communicate etc). If that view is taken then perhaps whether the phone was in use is just a question of fact for the magistrates to decide and they would bear in my mind the mischief at which the Regulation is targeted? If an actual call or text could be proved then fair enough. If the court accepts Police evidence that the driver was seen looking at the mobile telephone for a fairly lengthy period (e.g. several seconds) then perhaps the court might find as a fact that the phone was in use making or receiving a call or text or viewing something on the screen. If the holding of the phone was very momentary then perhaps a court would find that the phone was not actually being used. It's an interesting one and there does not appear to be a crystal clear and straightforward answer!