Panorama reporter Paul Kenyon has returned to West Africa to trace the route of African migrants as they attempt a deadly four-day crossing of the Sahara desert on foot. They set out unaware that the Europe they dream of reaching is deep in recession and the welcome less than warm. The man from the Libyan security services held a black beret over his nose. We had been walking in the heat for more than an hour across the dunes. Along the way we had seen discarded T-shirts and jeans, the occasional rucksack, and now this. The body was fresh, around two weeks old. It was that of a young man, clothed in a chocolate-brown T-shirt and faded jeans. There was no visible injury, no blood. He was lying on his back, propped awkwardly against the hot Saharan rocks. I crouched beside an outstretched arm and saw something had fallen from his grip. It was a plastic water bottle, empty and half submerged in the sand. The guard pointed back up the path. "Many more this way, many more," he said. Our trip to this remote part of Libya took place three weeks before the celebrations for Colonel Gaddafi's 40 years in power.

While the rest of the world's press struggled to get entry visas, and news of the pending release of the Lockerbie bomber from a Scottish prison not yet broken, we were embedded with Libya's security services in the Sahara desert.Weight Loss Surgery Covered By Bc Medical We were not looking for al-Qaeda, even though its followers are known to operate close to here on the Algerian border, we were looking for African migrants. Walmart Door CurtainsEvery year, around 40,000 of them cross the Sahara on their way to Europe. Pink Bathroom Sink For SaleWe found ourselves in the middle of the most dangerous migration route in the world. Most of those who attempt to cross here are economic migrants, but some are political refugees, fleeing conflict and persecution in places like Sudan, Eritrea and Somalia.

We had air-conditioned vehicles and huge tanks of water, but the migrants cross this part of the desert on foot. When the British Army patrol in similar conditions in Afghanistan, each soldier is supposed to drink 14 litres of water during a day-long operation. These migrants walk in the desert for four days, sometimes with just a litre or two of water, so that they can keep the weight down. The next body we came across lay with his wrist across his forehead, like he was wiping away the sweat. He looked about 18. His jeans had been torn around the left calf, probably by a jackal, and the flesh was torn away down to the bone. Nearby, there was another empty water bottle. It is a story that has come to dominate my life for the last two years. In 2007, an extraordinary photograph in the morning papers set off my work on this story. It was an aerial shot of a tuna net, in the middle of the Mediterranean Sea. Hanging from it were 27 men, clothed but with no sign of any boat. It seemed they had fallen from outer space.

When I finally tracked them down, to a hostel in Italy, it turned out they had been trying to cross the sea to Europe when their boat had capsized. They had clung onto the net for three days without proper food or water. None of them could swim, and they were so unfamiliar with the sea, they believed the tuna in the net were man-eating fish. "But how did you get the Mediterranean in the first place?" They looked at each other, puzzled. "We walked across the Sahara," they said. The youngest was a 19-year-old, from Ghana, named Justice Amin. As we talked I realised the journey he'd taken, that they'd all taken in the hope of reaching a "promised land" was of biblical proportions. They had not just risked their lives crossing the sea, they had first risked them on that walk across the desert. All of them had lost friends. They had been reduced to drinking their own urine on the Sahara, and drinking seawater on the Mediterranean. A quarter of those who attempt the journey each year end up dead.

Justice's story was particularly compelling. He had been raised by a witchdoctor, who spoke in tongues and sacrificed chickens on a clay idol outside their hut. Yet he could still speak four languages, and quote lengthy tracts from both the Koran and the Bible. He told me about the journey to Europe - about the nomads who lead men into the desert and then abandon them without water, the people smugglers who trick migrants onto boats without enough petrol to reach the other side and the Libyan border patrols who dress "like ninjas" and capture migrants on the dunes. I wrote a book about him, called "I am Justice", and now here I was, on the Sahara, with the very patrols he had tried to evade. We were back in the air-conditioned jeep when the radio message came through. They'd just spotted 21 migrants walking across the sand a couple of miles away. If caught they would be thrown into a Libyan prison. But if they were not stopped, they might just make it to the Mediterranean and the next step on this deadly journey.

Or, they might end up as corpses propped against Saharan rocks, arms reaching out for empty bottles. Panorama: Europe or Die Trying, BBC One, Monday, 14 September at 2030BST. E-mail this to a friendMost of us take an entirely positive view of Interpol, the cross-border crime-busting organisation, even though we have only the haziest view of what it actually does. This is at least partly thanks to the influence of Biggles, hero of schoolboy fiction, who used to go on perilous missions for Interpol to track down international felons. Agatha Christie was another powerful influence. Her Belgian detective Hercule Poirot might have a discrete word with well-placed Interpol friends when he wanted information on some master criminal. So far, so good. Unfortunately, Interpol is no longer the virtuous force it was. These days it doesn’t just chase villains. It aids and abets them. Its former president, Jackie Selebi, was recently found guilty of taking bribes from a drugs baron. More worrying by far, there is now overwhelming evidence that Interpol’s channels are happy to assist secret police from some of the world’s most vicious regimes as they target and then persecute internal dissidents.

It may once have been the case that it was the sort of organisation that helped honest citizens sleep more soundly at night. But many of the things Interpol has done over the past few years ought to wake us up at night, screaming. Let us consider the appalling case of Bill Browder, the former chief executive of Hermitage Capital Management, whose colleague Sergei Magnitsky died four years ago in a Russian prison, almost certainly tortured to death on the orders of the FSB state security service. Ever since then, Mr Browder, a man of courage and high principle, has demanded posthumous justice for Mr Magnitsky. In return the Russian authorities accuse the financier of corporate theft. Earlier this month, the FSB took its latest retaliatory action. It demanded that Interpol issue an “all points bulletin” to help locate Mr Browder – a move which is presumably intended to lead to his arrest and extradition. Any decent organisation would have dismissed this outrageous demand out of hand.

Not Interpol, which is expected to decide whether to comply with the Russian request at a meeting today at its Lyon headquarters. There is every chance it will, if precedent is anything to go by. Let’s turn our attention to Petr Silaev, a young political activist who was forced to flee Russia after taking part in a demonstration against the destruction of the Khimki Forest outside Moscow three years ago. He was wise to do so. Dark and sinister forces are behind the Khimki development, as I discovered when I visited the forest soon afterwards. My companions and I were trailed by plain-clothes police after we left, and we learnt that several journalists who exposed irregularities in the project have been brutally assaulted. One of them, Mikhail Beketov, recently died of his injuries. To return to Mr Silaev: after escaping from Russia he made his way to Spain, where he was seized by counter-terrorism police, acting on instructions from Moscow which had been circulated thanks to Interpol.

Let’s be clear: Mr Silaev is guiltless of any crime except offending the FSB. He was nevertheless held in a high-security jail for eight days, and cannot move outside Spain without the risk of being arrested again. The human rights charity Fair Trials International (which is preparing a report on the abuse of the Interpol system to threaten human rights activists, journalists and businessmen) has taken up his case and formally requested that his name be removed from Interpol databases; so far without success. As the Silaev case shows, Interpol is relaxed about collaborating with repressive regimes. There are numerous examples, the most disturbing of which concern the abuse of Interpol “Red Notices”, a high-priority system of alerts often used as a means of detecting suspected terrorists. In theory, these Red Notices should be welcomed by everyone, because they hasten the identification and arrest of desperate men and women who are a danger to us all. In practice, they have been perverted again and again to assist unpleasant regimes in persecuting domestic opposition.

Here are just a few examples. Chandima Withanaarachchi is a Sri Lankan blogger who delights in exposing government corruption and human rights abuses. Since there is no shortage of either in his native land, his website was banned, he lives in exile, and he is the subject of an Interpol Red Notice. Napoleon Gomez is a Mexican trade union official who campaigned for the truth after a terrible mining disaster, which he labelled an “industrial homicide”. The Mexican authorities responded by accusing him of corruption. Mr Gomez fled abroad, and lived under the menace of a Red Notice until March 29, even though as far as could be discovered no court had ever found him guilty of anything. He could scarcely move without being arrested, and could no longer do his work as an international trade union leader. Other countries which appear to have abused the Red Notice system include Saudi Arabia, Iran and Indonesia. I first became aware of the nature of the problem through my friend Mohammad Ali Harrath.

Mr Harrath, now a London businessman, campaigned manfully against President Ben Ali’s brutal Tunisian regime for many years, but was finally forced to flee the country. In his absence he was branded with a Red Notice and accused of an array of “crimes involving the use of weapons/explosives and terrorism”. Harrath’s Red Notice had been in place for 20 years by the time Ben Ali finally fell. Three months later, Interpol sheepishly removed it, telling him that “after re‑examining all the information in the file” it had concluded that the charges against him “were primarily political in nature”. It is telling indeed that Interpol reached this conclusion, two decades on, practically the moment the Ben Ali government had fallen. Privately, senior policemen tell me they know many requests are political, and how much they dislike handing sensitive information to certain regimes. However, Theresa May, the Home Secretary, foolishly pretends there is nothing amiss. Her spokesman told me yesterday that “the Home Office has no concerns about the way Interpol runs itself”.

But when I contacted Interpol last night, the answer was even more complacent. I was directed towards Article 3 of its constitution, which forbids it from undertaking “any intervention or activities of a political, military, religious or racial character”. The prohibition, the spokesman told me, “is taken extremely seriously by Interpol”. This claim is farcical. In truth, Interpol has never quite been the force for good that its popular image suggests. From the late 1930s to 1945 it fell under the control of Hitler, and for many decades thereafter it reportedly refused to help track down Nazi war criminals on the grounds that it did not get involved in “political” crimes. Now it’s in league with despots and torturers, as its handling of the Silaev case shows. Last night, when I spoke to the Home Office about today’s decision on Bill Browder, I was told that Mrs May didn’t want to know: “It’s a matter for the Russians and Interpol.” So it is entirely likely, on the basis of past form, that Interpol will today find with the FSB and against Bill Browder.