Sihanoukville, March 5:

Behind the tall fences and taller cranes of Cambodia’s sole deep-water port lurks a compound filled with rusty pipes and drilling equipment. Unlikely as it seems, this collection of shipping containers represents the best hope in years for the impoverished country still recovering from decades of war.

The base in sleepy Sihanoukville is US oil giant Chevron’s springboard for operations 160km off shore. It struck “significant” oil and gas deposits.

The initial find, estimated by the World Bank and United Nations’ Development Programme to be 400m to 500m barrels of oil, has already sparked something of a “black gold” rush with Chinese, Japanese, French and Korean companies battling for lucrative rights.

Yet international donors whose aid propped up Cambodia for years fear that a bonanza pumping up to $4.6 billion (GBP2.5 billion) into the nation’s coffers every year for the next two decades could make things worse. They warn that Cambodia could be blighted by the “resource curse” that has dogged so many developing nations.

Newly oil-rich countries with fragile state institutions have repeatedly fallen victim to sluggish growth despite vast earnings, leaving the poor worse off. The UN Development Programme points to Nigeria, highlighting how it grew more slowly than nations which had no resource windfall. Today 70 per cent of Nigerians live on less than $1 a day despite $450 billion in oil revenues in the past 35 years.

Diplomats fret that Cambodia, with endemic corruption and weak institutions that are the legacy of the murderous Khmer Rouge regime, could slide into the mire of a full-blown kleptocracy.

“At this stage we’re all rather nervous,” said one senior western diplomat. “Suddenly there’s going to be this avalanche of cash. There’s endemic corruption and a weak system of governance with few checks and balances on which these huge revenues will be imposed. We’ve only got two or three years’ leverage.”

Oil revenues offer huge new potential for corruption in a country that cleaves to its communist traditions of secrecy. Most oil contracts have been signed by the powerful deputy prime minister, Sok An, a close ally of the prime minister, Hun Sen, with the senior bureaucrats and even the finance ministry out of the loop.

Aid workers wryly look forward to the days of “Lagos on the Mekong” in a nation of 14m that is already “run like an episode of The Sopranos” because everyone gets their cut.

“Cambodia’s like a pyramid scheme of corruption,” said one development staffer in Phnom Penh.

Energy-hungry China is keen to get its hands on the oil. It matched international donors’ cash with a “no-strings” $600m gift last year as two global Chinese oil firms compete for contracts.