Insurance certificate is illegal for a printed copy document?

is it illegal for a printed document to be taken to the post office to get car tax for your car

Yes it is illegal!! The post office will not accept any copies of any documents. If you are in a hurry for an insurance certificate, get your insurance brokers to send you a cover note; this will be acceptable dont forget to also include your m.o.t.(if your car is over 3yrs old), and your log book or reminder note.
Hope this helps. :o)

I'm pretty sure you need the original.
Unless the copy was sent by yr insuranse company!

You will definitely require the original to tax your car.

It may or may not be illegal, it's certainly not acceptable.

Some insurance companies are online only, so the only certificate you get is in the form of a home printed PDF document.
These are perfectly legal at the post office, although some of the more backward or rural post offices might take some convincing of this fact. They generall get the gist when you ask them to ring head office to confirm their facts.

Also, some ins-co's, most notable RAC and Norwich Union Direct offer a 7 day driveaway scheme for private sales of second hand cars.
It's 7 days of free comp insurance to get it taxed and they give you a quote at the same time in the hope that you'll stay with them for the full year.
NUD do it for Ebay car sales only and RAC do it for all private car sales.
They email the certificate through to you in the form of a PDF document which you print out at home.
These are perfectly adequate for use in the post office when taxing your car.

It's not illegal but they wont accept it , it tells you on the form that copies wont be accepted .

not illegal, but they wont accept it