That's not how it works and it is not easily gamed.
You must provide your original passport, not a copy. And if you are a foreigner you must also provide a "share code" that allows the employer to go to the Home Office's website and check you details, including picture, and entitlement to live/work/study in the country.
Again, if some employers are unscrupulous, or just plain idiots, ID cards won't change that.
> by having copies of the documents they can show they did what was required and claim to have been misled and they are the victims, so no prosecution or fines.
You must provide your original passport, not a copy. And if you are a foreigner you must also provide a "share code" that allows the employer to go to the Home Office's website and check you details, including picture, and entitlement to live/work/study in the country.
Again, if some employers are unscrupulous, or just plain idiots, ID cards won't change that.
> by having copies of the documents they can show they did what was required and claim to have been misled and they are the victims, so no prosecution or fines.
On the contrary, this means 40k fine.