FIRST impressions, contrary to the old saying, are often deceptive. Time without number, you meet someone or hear them speak and say to yourself, yes, they’ve got it, they’re going to make a difference, they’re going to stay the course.

Then, a couple of weeks or months down the line, you come across them again and things just aren’t the same. The person, the message has faded, gone flat. So, slowly, sadly, you turn away and start to look again for the person, the moment that is genuinely lifechanging.

It was three years ago that I first met the Archbishop of York – or for York, as he likes to say – Dr John Sentamu. I wrote at the time that it was an inspirational and life-enhancing encounter. Our paths crossed again at the weekend when he came to perform a dedication service at St Barnabas, a busy and thriving church in central Middlesbrough that has just had some improvement work done.

If I had any worries about my first impressions of this remarkable man, they were very soon put to rest. I left the church more than ever convinced that this is someone who can change not just the church, but the nation and, indeed, the world for good: in short, an inspirational leader. Judging by the looks and body language of other people in the congregation, I was not alone.

Since our first meeting, Dr Sentamu has been a busy man. Apart from the usual round of church duties, he has made memorable and outspoken comments on Zimbabwe, the recession, what it means to be English and the sexual exploitation of women. He has also found time to do a parachute jump from 12,500ft for an Army charity.

Judging by that brief summary, you might get the impression he is someone who lives for, and through, the media. He has a talent for grabbing the headlines – cutting up his dog collar in protest at Zimbabwe’s oppressive Mugabe regime is just one case in point.

But he is more substance than sound-bite.

When you read his speeches and comments you feel inspired, but you also feel uncomfortable.

That is because his views on politics, morality and the world are challenging.

He is constantly asking us to look honestly at ourselves and see where we could do better.

Not many people can do that and get away with it. Dr Sentamu can because he is always honest and challenges himself as well as other people.

Take his comments when introducing the debate on the recession. He said that while bankers might be to blame, we were all – with our fondness for easy credit and reckless spending – responsible for the mess we’re in.

Inconvenient, unpalatable, but undoubtedly true, as were his comments that even in deepest recession we enjoy a standard of living that is the envy of two-thirds of the world.

He’s that rare thing in public life these days, a person of integrity who has scaled the heights, but remembers where he comes from and the journey he has made. In his case, a village in Uganda and a journey that has involved suffering and hardship as well as status and reward. He talks a language that people understand and relate to.

I hope I will see Dr Sentamu again soon. I hope you, too, have the opportunity to meet him or hear him speak. It is the only way to appreciate his presence and charisma – TV, radio, newspapers do not do him justice.

I am more convinced than ever that he does have the capacity to make a life-changing, even world-changing difference. You may dismiss that as a bit of Mallon hype – but I think I may be proved right.