IN Tim Burton's acclaimed 2003 children's movie Willy Wonka and The Chocolate Factory, Wonka's puritanical dentist dad - played by Christopher Lee - is enraged at his young son's plans to become a chocolatier. So Wonka Jnr threatens to run away.
Wilbur Snr counters: "Go ahead…. but I won't be here when you come back." The boy returns later only to find his father's house has vanished - leaving a gaping cavity at the centre of the terrace.
Later we see the mid-terrace house standing alone, tall and detached in the middle of a bleak snow-covered field.
The visual imaginatively conveys the self-imposed isolation of Wilbur but also shows us just how formidable a building the standard Georgian design townhouse is when seen in isolation.
These are mini mansions squeezed upwards and together in one of the smartest planning formulas ever devised for high-density city living. It is one we could look back to again today.
As well as maximising space, the aspect and window design flooded them with natural light. The fireplaces and chimneys were also clever passive air-conditioning devices and porous rendering allowed the buildings to breathe.
Today out-terrace townhouses built from the 1750s to the early 20th Century are a key hallmark of our cities and a big tourist attraction.
But now they have a problem. In a housing crisis, these fine buildings - the equivalent of three to five average family homes in each one - are falling down and standing empty. Many are on their last legs.
These buildings have most commonly been used to house bedsits which were recently outlawed. Rather than invest in the extensive conversions required, landlords simply sold up or are still trying. Around 5,000 bedsits were recently closed down, three quarters of them in Dublin.
Now these buildings require an investment of between €250,000 to €550,000 for new roofing, rewiring, plumbing, floor replacement, damp-proof courses - all within the context of the strictest preservation regime.
You can currently buy a three-storey over basement house in Dublin 1 for €300,000. This means you could have a city centre 3,000 sq ft home in top condition for €600,000. So what's going wrong? Why aren't buyers snapping them up?
Chartered surveyor Val O'Brien, who has surveyed hundreds of these properties, says: "The banks aren't lending money for this sort of work. Then there's fire regulations - you will need to invest big in fire-retardant doors and floors. And probably one of the most influential factors is the building regulations demand for conversion for the disabled - extremely difficult and expensive to do."
Different planners interpret preservation regimes in different ways. "What it all means is these buildings are full of uncertainties for buyers and so they avoid them."
So our city terraces are being regulated out of existence. Standing empty, they are in their most dangerous state - when flashing is stolen and lets in rain, and when the vandals start fires.
"The right kind of allowances in regulations have to be made so it is viable to invest. Local authorities must issue common preservation guidelines so that planners sing from the same hymn sheet," says O'Brien.
Otherwise, our crumbling historic terraces will be filled with four-floor high cavities that no amount of architectural dentistry will repair.