Of all the programmes, this was the most problematic to set up. Not surprising when you realise that this prison is one of the most secure buildings in the country.

The staff are rightly proud that no one has ever escaped from Long Lartin but it wasn’t the measures in place to maintain security that bedevilled the programme. More of that in a moment.

For a long time I had wanted to make a programme inside the prison and the Sense of Place project afforded me the perfect opportunity.

If you’ve ever travelled on the train at night between Worcester and Oxford you can’t fail to have noticed Long Lartin. It springs up out of the flat and fairly featureless Vale of Evesham. With its dazzling floodlights and strange curved walls it looks like something from the set of Close Encounters of the Third Kind.

Hundreds of local people work there and it houses some of the countries most notorious criminals and yet for the majority of us who only see it from the outside, it holds an air of mystery and menace.

A couple of other Sense of place producers in other parts of the country also opted to set one of their episodes in a prison. None as far as I know tried to get inside one of the few maximum security units.

Although it would have been easier to gain access to one of our other prisons, I knew that in Blakenhurst, for instance, prisoners were unlikely to have a "positive" relationship with their cell.

You can contact the series producer Howard Belgard by e-mailing howard.belgard@bbc.co.uk