Newham council houses around 25 young people per year, and generally will begin to offer housing to young people aged 20 years old. In the case of single parents they may do so from the age of 18, but never offer sole tenancies earlier than this.
They also require that young people be in EET, in order to maximise the chances of a successful tenancy (these criteria are waived in the case of single parents)
Offers will typically be made within the financial year, and will be either be from the council (£170-£180 per week) or a housing association ( £120-130 per week)
You will then be shown a property and must make a decision on that day, and will probably start moving in by the end of the week so it may be worthwhile to organise delivery arrangements beforehand.