I have been meaning to write this for the last few weeks. THERE IS HOPE. We started trying to train our DS at 2.6 as his pre=school (where he started 3 mornings a week at 2.7) insisted that they had to be trained. I retrospect I should have just ignored them - I had DD 3 weeks after he started bursery and he wasn't remotely ready. We plugged on for a few months but eventually, on the advice of a pediatridian, just gave up when he was 3.0. At 3.6 he was STILL not showing any signs and we relucatantly decided we just had to go for it and HOPE it would work. The first couple of weeks were an absolute disaster - he would wee if you took him but would NEVER ask and he flatly refused to poo anywhere excvept a nappy or his pants. I was in despair. It all culminated in DH taking his bottoms off and just leaving naked for ages at which point DS pooed on the floor in front of him. DH lost his temper (which I KNOW you are not meant to do) but it seemed to hit a chord as the next day, after an agonising hour of sitting on the loo, DS did a poo on the loo. Breakthrough. Importnantly, we bribed REALLY heavily with a really expensive toy we knew he wanted. Although bribery simply hadnt worked up till that point.
After that we had a few weeks of him performing as long you took him pretty regularly but he just wouldnt ask and then suddenly, almost overnight, he started asking. And we havent looked back. He is now 3.10 and we havent had an accident for a couple of months. I promise you I was IN DESPAIR. So don't give up hope.