Samaritans. From the UK you can call from any phone on: 116 123.
This post sparked an interesting discussion about the Samaritans, and I added that one of my family members was a Samaritan for 20 years and that there was a book of poetry called Listening Lines (Arrival Press 1995) that was written by volunteers and edited by Suzy Goodall. This is the poem of hers that was included, but there are many other touching ones in there, too. This poem was about a young homeless man living in King's Lynn, who visited Trixie at the Samaritans regularly, to talk to someone who cared, to sit in a warm room for a short while and drink a hot cup of tea:
He comes again,
Same life, same story,
No more strife.
He takes his life.