3.10 regression? ? help!

[celebmum]

DS has been completely toilet trained for well over a year (around 2.5) very occasionally has a night time accident but nothing out of the ordinary.
However since starting nursery in September he has started asking for a 'helper'everytime he need the loo, something he has never done before?! weve put this down to obviously some kids in his class do need a helper and have been told to ask and its just a habbit DS has adopted. But to coincide with this he has started/had an increasing number of soiled accidents. Or he will suddenly stop and shout out that he needs to go NOW/that a poo is coming, he claims that he doesnt know its coming or that it came out to fast etc.
he generally tries to get to the loo as soon as he realises and or clean himself up but its happening more and more and we dont know what to do!?

any advice? ?