Green: Enter without explosives or firing unless enemy targets are identified.

Amber: Enter firing. No explosive entry.

Red: Explosive entry using a grenade or charge. Enter firing at will.

What happened in Helmand's Sangin Valley in the spring of 2007 was nothing short of extraordinary. After the last gasp defence of the platoon houses by the Paras that preceded them in theatre, the soldiers of the Royal Anglian Regiment arrived in Afghanistan charged with taking the battle to the enemy. Despite brutal, debilitating conditions, the tour that followed became a bloody lesson in how to conduct offensive infantry warfare. Over a six-month tour of duty, the 'Vikings' battlegroup unleashed hell in heavy, relentless fighting that saw teenage soldiers battle toe to toe against hardcore Al Qaeda and Taliban warriors at unprecedented levels of ferocity.

The stories that emerged from the Sangin Valley, defined by bravery, comradeship, endurance and, above all, aggression, are remarkable So much so that Sandhurst manuals were re-written to incorporate the lessons of the campaign. But the fight was far from one-sided. May 2007 saw the Anglians suffer the highest number of British military casualties in any single month since the end of World War II. And those that did return home came back changed by the intensity of the experience.

In Attack State Red, Colonel Richard Kemp, a former Commanding Office of 1st Battalion, The Royal Anglian Regiment, and Chris Hughes, the Daily Mirror Security Correspondent, tell the story of the Royal Anglian's deployment for the first time. Combining the strategic insight of 3 Para with the adrenaline charge of Sniper One, they have produced the most dynamic, substantial and visceral account of the war in Afghanistan that's ever been written.