Tes is joining the Independent Sage press conference as it publishes its report.

Sir David King says there is a particular need to support BAME communities who are at higher risk from Covid-19.

Anthony Costello of UCL says they are concerned about risks passed on by children to people in multigenerational households or to others.

And find test trace and isolate is only just starting today, and there will be a 'lot of hiccoughs' with that approach and so delaying for a few weeks would give communities a protective shield.

Allyson Pollock says we don't know what's going on locally which is a really important factor to take into account. You also need to consider the risk factors in schools and communities - are the schools in deprived areas, with a high proportion of BAME pupils?

She says you need to think about school capacity to ensure small class sizes and social distancing.

Zubaida Haque of @RunnymedeTrust says a third of primary pupils and nearly a third in secondary are from BAME communities, communities with a higher risk from Covid-19. This has to be taken into account - without TTI in place, we can't guarantee we can protect vulnerable people.

David King says TTI needs to be operational for at least a couple of weeks before school openings. If R goes back to nearly 1, we are back to 'exponential growth' of this epidemic and we know opening schools could raise this.

Delaying opening for a couple weeks would reduce risk by a factor of 2 he says.