The Post Office is currently running a promotion via its Home Phone offer whereby they install and activate a new landline from BT Openereach for free until the 20th of May 2012; that's a significant saving as the standard cost of the line is £112.34.
In addition, there's no minimum term contract (except for a cancellation fee of £15, which means that you can move out after just 30 days.
The Home Phone offer includes evening and weekend calls to landlines as well as 0845/0870 and free weekend calls to UK mobiles and 40 international destinations. Note that the service does not include broadband.
In comparison, BT charges £130 for installing a new phone line with a standard line rental for landlines of £14.60 by direct debit (more if paid otherwise) plus you need to make two chargeable or inclusive calls per month. (ed : worth reading Cut Off In My Prime for those who are enamoured with BT)
We're not sure whether you can get two (or more) of those landlines connected to the location in which case one can envisage using Sharedband Bonded Broadband Routers to aggregate up to four lines together to deliver combined upstream and downstream bandwidth.