The Double Conspiracy - Richard Sloane

When an operation by the government and MI5 to replace the Queen with a double after she dies is leaked to a ruthless criminal mastermind, the Prime Minister calls in his oldest friend, Jack Sanderson, to sort out the mess. In a desperate race against time, Jack is sent on a delicate and highly dangerous mission to retrieve some incriminating tapes and must use all the skills he learnt while an MI5 agent to thwart the criminals. Amidst all the violence and intrigue, he falls in love with the double
but discovers in the end that she has secrets of her own to hide...

Set in the near future, this is the first in the Jack Sanderson series of political thrillers. Subsequent ones include Traitor in our Midst, The Dirty Bomb Affair and The Drone Attack.