If you haven't read Frank McCourt's 'Angela's Ashes' then you are missing out on a literary tour-de-force.

It conjures up a time in Limerick, Ireland, when poverty was rife and the workhouse was full. It was a time my parents knew well. It was a time of 'No Irish need apply' in the UK for jobs of any kind and a time in Limerick of violence, religion and wild passion.

Frank McCourt caught the atmosphere perfectly, evoking the clamour, bustle, energy and despair of a city typical in Ireland at that time.

It is the city where I was first given life by parents who could barely read and write. But I was soon swept over the Irish Sea in my mother's arms to a new life in England where conditions were just as bad for the poor but which was a country of great wealth and prestige and opportunity if you prepared to stick the prejudice and ridicule.

So it was a strange experience to return to Limerick albeit courtesy of Google maps. I haven't been back there in person for many years.

But I've been doing some basic plotting for a new Mike Delaney thriller as a follow up to 'The Immortality Plot' and for some reason set the story in the US and then over to Ireland. It must have been a subconscious decision to set the climax of the action in Limerick. It could have been Dublin, Waterford, Galway or anywhere. So I needed to remember the geography, the distances, the street layout and in so doing saw the street where my mother grew up and where I spent some formative years when I returned there as a child.

The old 'corporation' type houses are now painted like new pins and the city itself has grown and expanded.

Google maps is an invaluable tool, I discovered, for a writer to get close to a location. I needed to check out the positioning of King John's Castle and track back to a point where a sniper would be in sight of a target.

In the end, it was a good choice of location because it is a city fixed in my memory and in a mental time zone; a compartment of my psyche that still evokes an inexpressible emotion that is hard to define but which will never leave me.

So Mike Delaney will tangle with a truly terrifying adversary who follows him from the US to Ireland. I will say no more except that the provisional title is 'Good Girl Bad Girl'.