The post-war slum clearance was managed very very badly. The tenement accommodation in the Poplar area was awful in terms of physical living conditions but the communities in them were extremely close-knit from having grown up together over generations.
When people were moved out they were placed with no attention paid at all to these relationships. It completely destroyed community and many people lost connection with people who were as close as family to them, sometimes literal family members were also placed apart, and they lost valuable support too, especially women who would have gone from having a network of social contacts and childcare support to often nothing at all, apart from a husband who may have been abusive or drunk a lot of the time. It was expensive and a luxury to have a telephone at home and a car even more so, so they had no way to keep in touch with one another. Many people ended up extremely depressed and isolated. It is probably one of the factors which has led to tower blocks becoming such difficult places to live today. The decisions about where and how to relocate people were made by well-off councillors, mainly men, who had no experience of those communities and the supportive bonds that women often form in those situations, especially where leaving your husband was unheard of or terribly stigmatised. They didn't understand it and only saw the deprivation and terrible living conditions. It was well meaning but it was wrong, IMO.
You can see some similar community stuff having built up now in some of the older council estates where families have been living there for generations. Very loyal and closed within the community, extremely hostile and dangerous for outsiders - that is typically what happens where groups of people do not feel that authority such as the government, have their best interests at heart.
And evacuation was often a traumatic experience for children. A lot of farming families took evacuees in in order to use them as free labour. There was such a disparity of experience between the city-dwelling children and the countryside children that adults thought they were delinquent and they would often be beaten or ostracised. Plus very little understanding in those days that things like stress or anxiety relating to being ripped away from your parents (!) could cause behavioural issues, bed wetting etc. It was essentially luck if they even got sent to stay with somebody kind. I am sure there was also likely sexual abuse which went on but was not recorded or talked about, either by the hosts themselves or their own older children etc. Absolutely grim. Some of the children were shockingly young too, although the very youngest were evacuated with their mothers. I think it was school age which was the cut off, so four year olds.