We still co-sleep with DD at 3.5 and have done since she was born. I was in hospital for the first week and we co-slept there as well.
The HV and MW were very supportive for co-sleeping.
I'd read '3 In A Bed', all the Paul McKenna research I could find and I grew up in a country where co-sleeping was the norm and SIDS unheard of.
You do need to follow the rules though... you must be breast-feeding - the hormones will prevent you ever reaching the deepest stage of sleep and you will automatically lie in the 'safe' position: Arm above head so baby can't move up, knees bent under baby so they can't move down, body facing baby for easy feeding and other arm over baby to stop them rolling away. It's very similar to the recovery position and prevents you rolling onto the baby at any time either. A non-breast feeding mother will not automatically assume this sleeping position and there is much less protection for the baby plus they will sleep much more deeply.
Ads to that the whole no alcohol, smoking or drugs, must be a proper bed, absolutely no swaddling of the baby (lots of people don't realise that is a big no-no), light clothes for the baby, no pillows, duvets etc, no beds pushed up against walls, no father/baby co-sleeping, no older sibling co-sleeping.
We used a bed-bar with mesh to ensure there could be no falling out and that the surface was breathable (unlike most bumpers in cots). DD learnt to latch herself very quickly so I got lots of sleep because I wasn't having to get out of bed - most of the time I didn't even realise. DH has never had a night of disturbed sleep since she was born - she didn't need to cry as everything she needed was right there.
I also loved that I could wake up and know that my child was fine as I could feel both her heart-beat and breathing without having to move more than a finger. I would have been constantly checking on her in a cot in another room.
I feel it is the normal, natural way for a child to sleep. If cavewoman had left cavebaby 100 yards away on their own, they would have been sabre-toothed tiger food pretty quickly.
If we have another I will definitely co-sleep again.
It drives me crazy that falling asleep on a sofa is defined as co-sleeping, that suffocation or being rolled on gets classed as SIDS etc when neither are accurate. Also makes a mockery of the statistics. Would be so much better to give proper advice to people on safe co-sleeping.