The Lucifer network - Geoffrey Archer

TERROR KNOWS NO FRONTIERS
A deadly secret whispered by a dying gunrunner on a lonely road
in Zambia sets MI6 agent Sam Packer on a frantic race against
time. A terrorist gang has acquired a horror weapon but before
packer can discover more the man dies.

Packer is on his own, faced with skeptical colleagues and the
gunrunner's daughter Julie, who may hold the key to the secret
but who also suspects it was Packer who engineered her
father's death.

As Packer fights desperately to win Julie's confidence, the
unlikely pair follow the trail of murder and deceit from Scotland
to Vienna and on to a lonely island in the Adriatic: there they will
find not only the weapon but the identity of the sinister
organization known as the Lucifer Network.