Hi @jpdebono, thanks for your post here in the community.
The landline service from your side will work perfectly the same, apart from it will be connected to your Virgin Media Hub and use an internet based connection, rather than your standard phone line at the moment.
We have a full page of FAQ's and helpful information for the switchover process, as you're not alone in raising questions about this.
Please take a look at this link here and I'm sure this will put you at ease and answer any questions you may have.
If you've got any further questions after this, please don't be shy in posting any back on this thread and we'll happily help!
Many thanks
Tom_W