Six months of emails, clandestine meetings and confidential exchanges followed before arrangements for a visit to Britain were locked in. WikiLeaks takes security very seriously, and it is right to do so. After all, it's not paranoia when the vast intelligence and security apparatus of the US is arrayed against you. Consequently I flew out from Australia last month without a specific destination, only an instruction on arrival at Heathrow Airport to go to a certain railway station, taking precautions to see whether I was followed. There, using a public telephone, I phoned a number that had been provided earlier through a secure channel. A voice on the other end gave a single-word reply to my call - the name of a railway station outside London. I bought a ticket and some hours later arrived on a windswept, rain-splattered railway platform in rural England. Only a couple of other passengers got off and the platform was quickly deserted. I wondered what the next step would be.

But after a moment a figure emerged from the early evening shadows, with cap pulled down over his head and coat collar turned up, perhaps to make identification difficult but more likely to protect against the bitter wind and sleet. There was a quick greeting, then a long drive through the countryside to WikiLeaks's temporary headquarters, made available by a benefactor. I was greeted by the man himself: modest, unassuming, in T-shirt, tracksuit pants and socks with holes in them. Assange doesn't stand on ceremony and is always focused on the task. We got straight down to business - the imminent release, in conjunction with some of the world's leading newspapers, of a torrent of highly sensitive US diplomatic secrets. The setting was utterly incongruous. The home was a marvellous example of Georgian elegance, a relic of the pre-industrial age carefully preserved but demonstrating the challenges of maintaining buildings that are close to 300 years old.

On the walls of the drawing room, in effect WikiLeaks operations room, paintings of long-dead defenders of the empire, most in the scarlet uniforms, looked down on a tangle of laptops, printers, wires and power cables and other equipment. It is said the security-conscious Assange changes mobile phones as often as most people change shirts. This is an understatement. Tables were covered with mobile phones and SIM cards were strewn around like confetti. Resting in one corner was Assange's backpack, carrying all his worldly goods. In the morning the countryside reverberated to the sounds of gunfire as the English upper class indulged its passion for bird shooting. Occasionally low-flying air force jets would rattle the windows, prompting jokes about a possible air strike. For a tiny organisation under immense pressure the atmosphere in temporary WikiLeaks HQ was remarkably calm and relaxed. On the eve of its biggest documents release, the main work area was often silent apart from the sound of typing as documents were formatted and last-minute communications made with the newspapers partnered in the release. Although WikiLeaks has a big pool of volunteers, the inner core is a small, highly committed group, all working on the basis of only expenses being reimbursed, with remarkably diverse skills ranging from computer programming and language translation to journalism and media liaison.

It is a truly multinational enterprise, with accents from around the globe heard across the breakfast table. Not that everyone appears at breakfast. WikiLeaks runs on a 24-hour, seven-day-a-week basis so a good proportion of the key personnel are essentially nocturnal. As for Assange, he is an impressive figure. Highly intelligent, articulate and deeply committed to his cause. And he certainly isn't in it for the money. For someone under immense pressure he was remarkably calm, focused and measured. Contrary to reports that he is an eccentric egomaniac, he gave every appearance of being good-tempered and humoured, ready to discuss issues and carefully consider advice. He is certainly a strategic thinker with a fair amount of political and media nous that has turned his organisation into a global phenomenon. Having entered into talks on the basis of confidentiality, I will not repeat his observations but I found him a highly engaging, thoughtful conversationalist.

He pays close attention to political developments in Australia and has a keen sense of the importance of encouraging more openness. A frequent theme is the need to cut through the hypocrisy and cant that fills so much of political discourse by enabling citizens to see and hear directly what their leaders think and say in private. Assange has well and truly kicked the hornets' nest. He is now in an English prison awaiting extradition proceedings that could mean he will be taken to Sweden to be questioned about sexual misconduct allegations, but which could also open the door for him to be sent to face the wrath of the US government. It is reported that he is in good spirits and as a highly self-contained person he probably has the inner resources to cope with his difficult circumstances. Loading

Whatever the outcome of these proceedings, one thing was clear. He has given much thought to how WikiLeaks might defend itself from sustained attacks and how it might function without him. The frenzy about WikiLeaks is likely to continue. There will be twists and turns but it looks like WikiLeaks is here to stay and governments will have to get used to that. Philip Dorling is a Canberra writer and Fairfax contributor.