As well as what MrSaffron says there is a Line Rental Saver, where you pay a discounted amount for the year.
Currently it is a bad idea to take that, as it has a 12-month term that overlaps with your broadband. They don't have the same contract dates.
This can lead to complications if you want to leave.The discount offered used to be considerable, so it may have been worth the potential hassle, but it is quite small now. Up to you what you decide, of course.
If you just want to cut your phone bill, I went to Pulse8broadband for that, while I still had my broadband with Plusnet. I pay £13 per month rental, plus £1pm caller display, no call plan but 1ppm calls with no setup fee. Peanuts.
The indispensable man or woman passes from the scene, and what happens next is more or less the same thing as was happening before.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - AAISP Home::1 80/20. Sync 59997/15142kbps @ 600m. - BQM