I have a friend who is on income support and does not currently have a landline. She relies entirely on mobile phone and broadband. BT do their "Social Tariff" phone service for £4.50 per month and this allows you to have BB on the line, unlike their earlier "Basic" service.
I think you can anticipate the question. Does Plusnet have a similar scheme? This scheme plus PN's basic broadband at £3.24/month for 12 months would be an ideal combination for my friend.
A related question concerns landline installation. She has been in touch with BT who have asked if there is a landline physically present at her flat. SHe wasn't sure so I'll go over there to see if there is. BT said that if there is a master socket they can supply their service without any extra charge. I'm slightly surprised at this because another friend moved to a house which had a line physically present but it was LLU'd by the previous owner. All phone suppliers wanted to levy an installation charge but they were fortunate that BT were doing a free instal at the time in return for an 18 month contract. I don't know what I'll find. It might be a "dead" line. It might be live but previosuly LLU'd. Any other possibilities?