By the year 2015 they are to fully replace old internal passports.

When the old passport with the Cambodian visa has run out.

Fairly sure OK overland, but last did that 4 years ago in my old passport.

You will be allowed to retain your old passport while waiting for a replacement to be processed and returned.

The identity page on older Irish passports was on the back cover of the booklet.

Failure to do so may leave your old passport open to abuse.

For a new passport you need to hand over the old passport.

Your old passport will then be handed back to you, to keep for ID purposes.

You do not have to wait until your old passport expires to renew it.

This was to ensure that when they cut the corners off the old passport they would not damage the visa page.