It doesn't use the phone line for the service.
However the reason I clarified is because with pretty much any alternative broadband provider (apart from perhaps Virgin Media cable) you are required to have a phone line (and pay line rental) to get the service, whether you use the phone line for calls or not. So it's a little unfair to compare the £62.50 Hyperoptic 1Gbps (with phone line) service cost to a £26 per month cost for Infinity (76 Mbps down / 19Mbps up) where you have to also pay £15.99 for line rental, so overall cost of £41.99 per month.
Plus some of the new customer offers (again, differs by building) are up to 6 months free, which (if your particular building gets that offer) can make the effective cost over a 12 month contract £31.25 per month.
I got 3 months free in my building, they are now offering 6 months free in the building for new customers, although I'm not too bitter as it's luck of the draw sometimes as to when you sign up so can't really complain.