Yes how old is your son? Makes a difference if he's a toddler or a teenager.
But I would agree with your support worker and ignore the behaviour, this tactic takes time and usually involves the child making more effort to get your attention at first until they are 100% convinced that you will just ignore them every time no matter how far they push you. When they get worse take it a sign there getting the idea and your near the end, give in just once and your back to square one as it proves to them that there efforts will eventually pay off.
And echo what willow has said, well done for getting out, your obviously a strong person so you will get through this phase with your child so hang on in there ok.
Is it possible for you to keep track of what happens just before the behaviour occurs, the actual behaviour and your reaction? Do this for a few weeks and you may see a pattern (i.e. he does it when leaving nursery, or he does it after being told 'no, etc).
Feel free to email or call me if you would like to chat more about it.
dear Willow. many thanks for that. it was a long and drawn out process but worth it in the end. My son is........ 3 (Is there such a thing as terrible 3's?) xx