For four characters the 500 quid worry bead in their pocket may be both a blessing and a curse.

For elderly Dr Zachary Busner, it's his lifeline to his autistic grandson Ben, whose own connection with technology is, in turn, a vital one.

For MI6 agent Jonathan De'Ath, aka 'the Butcher', the phone may reveal his best kept secret of all: that Colonel Gawain Thomas is his lover.