Infiltration — Gavin Deas

This groundbreaking collaboration between two Gollancz authors tells of the invasion of Earth by two different alien races - at the same time. Two men become aware of the threat, and must work to sabotage the invasion plans and see off the aliens.

Each book follows one hero, uncovering the threat to humanity and the world from their point of view. Each book can be read on its own, and will give the reader a complete, kinetic, fast-paced military SF story. But read both books and the reader gets something else - another view of (some of) the same events and crossover points, culminating in a bloody battle at Canary Wharf.

The two books can be read in any order, but together they tell the story of humanity caught in the crossfire between two deadly alien races, who have made Earth their battleground...