The almost complete six-bed properties were found to be up to a third bigger and in different locations than allowed under planning rules.
Their plot is now little more than a pile of rubble after the final home was razed to the ground this week.
Councillors ordered the demolitions on the West Pennine Moors near Bolton, Lancs, in 2018.
But legal wrangling with developer Sparkle Developments and pleas from homeowners meant the work to take them down did not start until May last year.
An inquiry heard how plot one had a 31 percent bigger footprint than allowed, while plot two was 19 percent bigger, plot three 32 percent bigger and plot four 33 percent bigger.
The developer had claimed the enforcement notice issued by the council to demolish the homes was excessive and too harsh to remedy any breach in planning regulations.
And Elan Raja, who owns one of the mansions, told the hearing he'd faced a "nightmare" as he begged for his house to be left standing.
He said he paid £1,057,000 for the plot in 2016 - but has since spent more than £215,000 on the rental of an alternative property and other costs.
"It has had life-changing consequences for me," he said.
"I feel trapped in a vicious circle with deepening financial pressures and effects on my family.
"Every day feels like I'm waking up to a nightmare. The best way to describe it is a pressure cooker."
In spite of his pleas, the properties have now been torn down.
Councillor Andy Morgan said: “It’s the right thing to do.
"There are two applications for individual plots to be built with slight alterations.
“The intent is to rebuild them and save much of the materials.”
While minor improvements to your home may not need planning permission, any major works will need the council's go-ahead.
You'll need planning permission if you're going to build a new property, make a major change to your existing home, or change the use of a building.
To find out if you need permission, contact your local council.
You can also search a register of planning decisions, to object or comment on proposed works in your area.
After you apply, you local authority will decide whether to grant permission.
It will take into account factors such as the number, size and appearance of the buildings, and how your development would affect the surrounding area.
You'll usually find out the council's decision within eight weeks.
If you're not granted permission, you might be able to appeal.
If you carry out works that require permission without getting it, you can be served an enforcement notice, which will order you to undo all the changes you've made.
You can appeal an enforcement notice, but it's illegal to ignore it.
Homeowners have been left devastated by the decision
The almost complete six-bed properties were found to be up to a third bigger and in different locations than allowed
Councillor Andy Morgan said: 'It’s the right thing to do. The intent is to rebuild them and save much of the materials'