Thanks for your replies and advice ladies.

LS, I did consider pulling down the rails, I might even do that first, I just think the mattress is quite high off the floor if he fell down? I went to see a friend with a 3 and a half year old who's been in his big bed since he was almost 3, and it seemed quite low to the ground, plus she has a safety rail on the side for him. Once I take the sides off there won't be any safety rail. The other thing is that he rolls quite a bit in his sleep so I can see him falling out a lot. I'll give it a go though, that will give me a chance to see how often he tries to escape and how strong my will power is! lol.

Ausgirl, no day sleeps here anymore unfortunately And I think you're spot on, it doesn't matter when he is moved into a big bed, he will attempt to flee it anyway to begin with, as he loves to sleep with us. Doesn't matter if he is 2, 3 or 4!

I think I will take the side rails off like I've said ladies, and give it a couple of months but I will slowly organise a big bed for him. I figure I can always lie down with him when he needs a bit of soothing to sleep (currently I stay in his room for 5 or 10 minutes until he is really relaxed and then I walk out).

Thanks agian for your advice!