Toxic smog and 'blood rain' set to hit UK as experts urge people to stay indoors

smog alert has been issued for parts of the UK.
A cloud of dust from the Sahara will hit Britain on Thursday.
Southern and central England will be affected, with eastern areas worst hit.
The Department for Food, Agriculture and Rural Affairs (Defra) has issued alerts across southern and central England.
A level-8 red warning is in place for eastern regions with toxic fog and dust threatening to engulf the region.
Health experts have issued emergency earnings to people with asthma and other conditions to stay indoors and avoid exercise.