A school has been closed for a fourth day after 30 teachers fell ill following a staff Christmas party.
Churchfields Secondary School, in Swindon, was shut to nearly all pupils on Monday lunchtime, though the school's website said Year 11 pupils should come in as normal on Thursday.
The Health and Safety Executive has started an inquiry, the results of which are expected in a fortnight.
Head teacher Steve Flavin said the sickness "may be in relation to food".
Speaking earlier in the week, Mr Flavin said: "We had an event on Friday evening to celebrate our successful examination results at a hotel in Swindon and that's not being ruled out.
"But that's not through over-indulgence. It may be in relation to the food because it was a sit-down meal."