This is a thorny question that I have been grappling with since my dear lovely Mum died last year. She was a truly wonderful personality and much loved by most people who knew her. Owing (I think) to early negative experiences she had with religion, she got 'turned off' Christianity and was always rather cynical about it, so didn't attend church or show much interest in conventionally accepted Christianity. As far as I know she did nothing much wrong in her life, was a very honest faithful person, great sense of humour and full of integrity. (It was easier and pleasanter to be in her company than in that of many Christians I know!) I miss her a lot, do have a personal Christian faith, and hope/need to believe that I will see her again one day in the 'afterlife'. Many interpret the Bible as teaching that those who do not openly 'accept Jesus as Lord' are automatically destined to be excluded from Heaven - and this is my problem.
- I know what the Bible says/ what Jesus taught, ie that He alone is the way, truth and life (...and tried to explain this to my mother a few times ....so she had definitely heard the gospel). I do not judge her personally, and my gut feeling is that a good and loving God could not possibly condemn such a person to the outer darkness. Not only her, but several other people very dear to me have died in recent years, and were not 'clearly' Christians, but their lives spoke volumes about their goodness and love for others. So, can a good loving God really reject such people after death?
I would love to find something to cast light on the question - even if it doesn't necessarily give me exactly the answers I would like to hear...I suppose I am seeking some solid and reliable theology to comfort me, not to increase my sense of loss (that someone so dear must have missed out on eternal life....IYSWIM). Thanks to anyone with some insights here.
I think (speaking as a Christian) that it is easier to feel comfortable with the death of a person who has publicly said to you 'Jesus Christ is my Lord, I want Him in my life'. It's very hard when you don't have that but I reckon the God who loved us so much that he endured the cross is going to love us enough to have an open door wherever possible. Nothing is impossible for God. Nothing is beyond Him and remember Romans - that nothing can seperate us from the love of God, neither angels nor demons, nothing (haven't got time to c&p the proper quote sorry). I think we don't give the love of God enough credit. That's not to say you can live as you like and deny him and it will all work out fine but I think there are some (most?) people who are very close to faith, even when they don't know it. Think about how often people in extremis pray when they've never had a faith before when trouble hits. Panic? Or a deep seated faith that's at our core? 
for your kind, wise and enormously helpful words: every single post here has done something to reassure and console me on this tough issue. We actually used Romans 8: 38-39 at my Mum's farewell service; as well as the first few verses of John 14 ('In my Father's house are many mansions...'). I read somewhere else too a helpful text something like: 'God hates nothing that He has made', but can't trace that specific text just at the moment.