Alistair Campbell

Absolutely.

A lot of people were on the record back just over a year ago saying, he's never going to be toppled.

Don't be ridiculous.

There's no way a small group of Al-Qaeda fighters from the Northwest are going to be able to take the whole country.

And of course, regimes, when they want to really oppress people, they can do it.

We saw it in Czechoslovakia and Hungary during the Cold War.

And then we saw the opposite, of course, in 1989, where regimes that seemed like East German regime, you know, with millions of people in the stars that you suddenly fold.

So what are the only ways of trying to work out what the likelihood is here?

I think the first thing is to look at ideology.

So one of the things that's different about this regime compared to, you know, the communist regimes in Poland or Hungary in 1989 is that the ideology is still very strong.

Amongst the true believers, there still is a hard core of clergymen, Revolutionary Guards people, the Basij militia, which is more of a kind of village level extremist militia.

13 million of them voted for the more hardline candidate in the last elections.

And certainly the guy at the top, Ayatollah Khamenei, is somebody who was badly wounded in the revolution and gives every impression of being a true believer who's not about to flit off to Moscow on a plane.

So it's a bit different, I guess, to an exhausted communist regime or Gaddafi or Saddam Hussein or even Bashar al-Assad towards the end, which had become sort of personalist regimes.

That doesn't mean, though, that you might, for example, find the army

which is much less ideologically motivated traditionally than the Revolutionary Guard and the Basij, beginning to defect and split.

Any other thoughts on how you can tell whether regimes have had a fall or not?

I was looking at the mini revolution, do you remember, against Gorbachev?

So 1991, where suddenly the tanks rolled out and there was a coup d'etat and the head of the KGB and everybody toppled him.

And then Yeltsin appeared on tanks and, you know, women marched along the bridge in Moscow.