For example...
Gordon brown introduced working tax credit.
Great! You think. An income boost for the poorest - what's not to like?
Actually all this did was allow employers to pay unsustainably low wages to employees. In an ideal world this would mean more job creation, in reality, it simply means higher corporate profits, which tend to flow to the wealthiest.
It also has a negative impact on productivity and allowed Britain to become trapped in a low wage economy. If you have to pay more to attract staff, zombie or badly run businesses don't survive and well run ones do. If you have to pay staff more to attract them, they are more valuable, an employer also needs to get more from the employee so its worth investing in training them, an overall productivity increases.
Look what's happened recently. I was against Brexit generally but the one aspect of the EU I disliked was the labour oversupply it created. Having left the EU, wages are rising in many areas that depended on cheap EU labour suppressing wages.
I honestly believe WTC suppressed wages for those at the bottom and allowed more profits to go to those at the top, contributing to the current hideous wealth gap we have in the UK, so despite being a long term labour party member, Gordon brown would not be who I would choose to reinstate.