It has been just days since votes were cast in the second round run-off of the presidential elections in Ukraine.

The protesters' defiance makes it hard to run Ukraine

In the capital Kiev and many cities to the east, supporters of the opposition leader, Viktor Yushchenko, continue to dispute presidential poll results that indicate Prime Minister Viktor Yanukovych is the winner.

Exactly a week ago, as Ukrainians prepared to vote in their presidential election, I was in Kiev. A chill wind whipped through the city. It brought a cruel and biting cold.

Perhaps it was a warning that Ukrainians should steel themselves for the trials to come.

This city, with its attractive tree-lined avenues and ornate, sometimes crumbling, buildings was given its first dusting of snow this winter.

Sea of colour

Huge soft flakes clung to everything, turning all of Kiev a clean and brilliant white. A week on, looking back, it's almost as though Kiev was being readied, the city wiped clean.

Now the snow is still there but it's smudged everywhere you turn with a new palate of colours, orange the colour of opposition and just occasionally, government blue.

Ukraine's disputed election is forcing everyone here to choose sides. Kiev is opposition land. Everywhere you look there is orange.

DISPUTED ELECTION Official result: Yanukovych (left): 49.46% Yushchenko: 46.61% Western observers report: Abuse of state resources and "overt media bias" in favour of Mr Yanukovych State workers pressured to give absentee voting certificate to their superiors Intimidation at some polling stations Suspiciously high turnout - 96% - in the key pro-government region of Donetsk Turmoil in pictures Support for Yanukovych Was Yushchenko poisoned?

The huge crowds who have taken to the streets have orange flags, orange clothes. The receptionists at my hotel are in orange. Some people even have their cats and dogs in orange.

By the end of the week, Kiev's streets were a shifting sea of orange. You could watch the currents come and go in orange eddies and swirls as new groups marched through the throng.

On Friday morning five days into Ukraine's popular revolt, I was having to force my way through the barricades.

They had sprung up all over the centre of Kiev, on every street, paralysing government.

People were blocking the entrance to every official building. By sheer force of numbers, with one simple act of standing out in the snow, they have made this country almost impossible to run.

I had arranged a meeting with an ally of the prime minister, the official winner of the election. He couldn't make it.

He wasn't able to cross the barricades. When I eventually found him, he was looking a little shaken.

"Can you believe it," he said. "They wouldn't let me through. They cried 'shame, shame' at me. I feel hunted, like a fox."

Power of the people

I have seen revolutions in the Philippines and the former Soviet Republic of Georgia. The dynamics on the streets are fascinating to watch.

The way the crowds build until they reach a critical mass, so large that almost nothing can stop them. The mass senses it has enough power to face down the state. You can feel it in the air.

In Kiev on Friday that tipping point had almost been reached. I watched as squads of police cadets marched down the hill in double-quick time to join the protest. People lining the pavements greeted them with cheers.

" In Kiev, the energy is everywhere. You can feel it crackle like electricity in the air "

Some from the military and police have started siding with the crowds, another sign that authority is ebbing from the state.

Outside the presidential offices was a group of women face to face with a line of anxious riot police.

"Smile at us. Smile," the women taunted, unafraid. One of them, an old lady who walked with a stick, then turned her attention to me. "Young man," she said, "you must wear a hat in this weather or you'll catch a cold."

There are other things that are fascinating too. Uprisings like this, I've learnt, don't just happen spontaneously.

Feeding the protest

The level of organisation is incredible. In just a week, Ukraine's opposition has created a network to sustain its protests.

At opposition rallies armies of middle-aged ladies now come round with boxes of sandwiches, cups of tea and chocolate, offering them for free, to keep the protest going, despite the cold.

On the giant stage and screens in independence square, there is a carefully choreographed flow of rock groups, pop bands, choirs, opera singers and even comedians to keep the crowds entertained.

And opposition supporters who come from the regions are given warm clothes and found warm places to sleep.

But what is most important of all to any uprising like this is the motivation, the energy of the crowds.

As I look out of my window, they are swelling again for another day of protest. It is these people's conviction that this is a crucial moment for young democracy.

They want a decent and tolerant society. They will not accept a president who they believe has manipulated his way to victory.