British soldiers were abandoned behind enemy lines after a secret mission went disastrously wrong, their commander has revealed after almost a decade of silence.

For the first time, Captain David Blakeley, 33, has spoken of how his patrol of just nine men were surrounded by hundreds of Saddam Hussein’s most feared troops after being sent far ahead of the frontline during the initial invasion of Iraq.

Based on hopelessly inaccurate intelligence, the Pathfinders – an elite airborne specialist reconnaissance unit – had been dispatched to recce an airfield hundreds of kilometres north of the British position for a potential airborne insertion of paratroopers. The area, far from being “relatively benign” as they had been told, was swarming with Republican Guard and Fedayeen. Realising they were boxed in and out numbered, they called for air support only to be told none was available.

Alone and surrounded, they fought their way back through repeated ambushes, saved by incredible luck and valour that would earn the unit two Military Crosses.

“We were massively outnumbered. We were abandoned and betrayed by higher command. If we had all died I am sure the blame would have been placed on us, on me in particular,” Capt Blakeley told The Independent, adamant that every one of his “awesome” soldiers deserved recognition for their bravery that day.

Seriously injured in a later mission, Capt Blakeley – second in command of the Pathfinder Platoon - left the army. Nine years on he explained that he decided to break his silence despite, knowing he would have to fight the might of the Ministry of Defence and risk being ostracised by a unit known for vociferously guarding its privacy. In a fortnight's time Pathfinder – A Special Forces Mission Behind Enemy Lines – will reveal the entire operation as well as the ugly story of how they were left to possible capture or death by their senior commanders.

“I think it is the biggest secret of the war. I know I am going to get some snipes from people who think I should have kept quiet. It has been a lonely journey but morally it was the right thing to do. The key reason was to learn lessons from the mistakes," he said.

It was just days into the Iraq invasion and the six Pathfinders and three Royal Engineers had been sent north of the American front line to recce Qalat Sikar airfield – 120km north of Nasiriyah.

On 23 March 2003 they reached Nasiriyah, where the US Marine advance had been stalled by unexpected resistance in a battle that would cost them 29 men. Aware they had just 12 hours to complete their mission, the British patrol of three land rover WMIKs, loaded with six machine guns, moved through the frontline at last light, passing “zombie like”, shell shocked marines still recovering their dead.

Relying on US intelligence, they were stunned to suddenly find themselves in the middle of an Iraqi camp, Capt Blakeley explained: “They didn’t do anything because it was so outrageous. They didn’t expect us to suddenly move through their position.”

Now 80km north of the frontline, sporadic fire turned intense, continued the former officer: “We started to hear the crack, it was getting closer and Tricky who was on the 50-cal (heavy machine gun) said he could hear mortars so we pulled off the road in a snap ambush, using the cover of some trees.”

They watched as the headlights of 15 pick up trucks, each carrying a dozen of Iraq's feared Fedayeen in their distinctive white uniforms, drive past and realised they were trapped behind enemy lines.

Unable to go north or south, they headed east towards their objective only to find themselves boxed in by a canal, shadowy armed figures in the near distance. Debating whether to finish the last 40km on foot, they decided their only advantage was the speed and firepower of their vehicles and agreed they would call in air support.

“I was told instantly by a senior officer there was no air. It was like swallowing acid. They didn’t say wait out, we were not told they would try. Tricky said ‘ask again for combat recovery’ but I was told again there was nothing available. It was crushing, devastating. We were totally on our own, abandoned.”

In case of their worst nightmare of capture, they disabled their radios so they would not fall into enemy hands and decided their only option was to fight their way back through: “Tactically it was completely the wrong thing to do but it was the best decision to be made. We hoped the plan was so outrageous we would have the element of surprise.”

Capt Blakeley praised the bravery and incredible presence of mind of the men as they fought their way back through five ambushes, past Iraqi bunkers and machine gun positions, rocket propelled grenades firing over them: “It was like Star Wars. The intensity of fire was like nothing I have ever seen. We were stupidly lucky.”

Finally they arrived back at the American position, their vehicles riddled with bullet holes. Capt Blakeley had one through his trouser leg while another soldier had a round embedded in the pistol on his chest. They passed on grid references on all the Iraqi units they had encountered to the US Marines but say they received little initial praise from their immediate commanders.

“The mission had failed but we had done our damnedest. I was “interviewed without coffee” and asked why I had continued, given the situation in Nasiriyah. When I thought of these amazing guys and what we had contributed to the intelligence picture, I was shaking with anger.”

Injured when he was crushed under vehicle that rolled on a later mission, Capt Blakeley recovered fully but left the army in 2006. It was not until he was approached by a literary agent that he eventually agreed to write the book, despite knowing he would face a long battle with the Ministry of Defence - which eventually cleared it for publication on 17 May - as well as anger from some sections of the military.