It was April, 1975. I'd been stationed in the north of South Vietnam, working as a nurse in the military's clandestine cosmetics division - a black project so buried it didn't even have an official name. Our task was slipping American Commandos up past the border, disguised as Vietnamese farmers indistinguishable from the locals. It was gory work, but as the war began to wind down towards its conclusion, so did the work.

Our medical camp was remote, swallowed by steaming jungle on all sides. The surgical beds lay empty, and with nothing else to do we'd settled down for another dull day playing cards, drinking lukewarm beers, and swatting at the mosquitoes. I remember the radio was always on, crackling with music. That day, it was the news:

"The temperature in Saigon is 105 degrees and rising," said the broadcaster.

Well, I aint ever seen the military men move so fast before. Our little forward medical camp became a scene of chaos. Playing cards were thrown down. Supplies were packed. Jeeps roared away in clouds of red dust. They were back before nightfall. The roads were no longer safe.

It didn’t take long to learn the truth. Saigon was collapsing. The "orderly withdrawal" that command had been insisting on for weeks had unraveled into chaos. Viet Cong forces were streaming south faster than anyone had predicted, their tanks eating up miles of highway at terrifying speed. Our position was now fully cut off from evav. The road to Saigon was gone, and the clock was ticking before the VC came knocking.

But the real disaster wasn’t about us. It was the thousands of men we'd worked on over the years - American operatives buried deep in North Vietnam as farmers, soldiers and wives, living lives with bodies we'd meticulously crafted for them. Men whose faces and bodies we'd meticulously catalogued, both prior to surgery, so that we'd know how to revert them when it came to it, and post-surgery, so we'd recognise them when they returned to the fold. Photos. Documents. Fingerprints and x-rays. If the Viet Cong got their hands on those records, our Commandos would have their covers blown wide open, followed shortly by their brains.

There was an argument about what to do but the situation demanded only one thing. We stacked the crates of paperwork high and by nightfall, the jungle glowed orange with the bonfires, ash whirling upwards through the whirling helicopter blades. We knew we were watching lives going up in smoke. Even if the men did return, there was little chance that their families would ever again look upon the faces that we had so meticulously recorded.

But the records weren’t the only problem. Hundreds of us remained 0 surgeons, nurses, and support staff - that knew too much. If the Viet Cong captured us, it would be straight to the Hanoi Hilton to be squeezed for every name we could recall. So began the evacuation, Operation Facelift.

We worked day and night, altering people with the skills we'd mastered over a long war. Supplies were dwindling - skin grafts, silicone, everything. There wasn’t enough to turn all of us into Vietnamese men, so we had to make compromises. To conserve material, we went small. Petite. By the morning, a steady stream of dainty Vietnamese farm girls were limping out of the surgical tents and starting their journeys towards the nearest villages.