Hundreds of pupils have been sent home as a flu outbreak sweeps through schools.

Staff and students have been struck down with the virus and in some cases there have not been enough teachers to take classes.

To make matters worse, there are not enough supply teachers to fill the gaps.

One of the worst-hit is Warden Park School in Cuckfield where 225 students were off yesterday.

Deputy head teacher Martin Hooper said: "I have never experienced anything on this scale in the five years I have been here.

"At its peak 400 children were ill along with 15 members of staff.

"Around 100 pupils are going through the medical room every day and on average for the last week there have been 300 pupils and 13 teachers off sick every day."

The entire year nine, around 300 pupils, at Warden Park was told to stay at home yesterday.

Mr Hooper said: "Year eight was asked not to come to school this morning and year seven will be given the day off on Friday."

Schools in Brighton, Hove and Worthing have also been affected.

Liz Fletcher, head teacher of Patcham High School in Brighton, is hoping the illness is coming to an end at her school.

She said: "Last week flu was a huge problem. It seemed to sweep through the school.

"A lot of students and teachers I have known never to be absent were off.

"This has been the worst flu outbreak to hit the school because so many people have been ill at the same time, although I have known bugs hit the school for longer periods."

Staff at the school have helped to cover lessons and supply teachers were drafted in.

Other schools have been unable to get enough temporary staff as the huge demand for supply teachers has put pressure on agencies.

A spokeswoman for Time Plan, which has 140 teachers on its books in Sussex and Kent, said: "Head teachers are ringing us up because their permanent staff are falling sick and they need day-to-day supply staff.

"We do not have enough staff to fill in the gaps because we have persuaded day-to-day supply teachers who used to be on our books to take longer term or permanent positions because the need is so desperate."

Yesterday morning up to 15 schools in West Sussex and Brighton and Hove had called Time Plan for staff, but the company had to turn headteachers away.

Official figures from East Sussex, Brighton and Hove Health Authority for the week ending January 31, showed the highest levels of flu this winter.

In the southern region, which includes Sussex, there were 37 cases of the illness for every 100,000 people.

The health authority has given advice to the public telling them what to do if they are unwell.

Dr Rachel Joce, a consultant in communicable disease control and chair of the local flu group, said: "Unless you are very unwell or are particularly vulnerable because of age or an existing health problem, self-care is the best option for flu and other viruses."

People are advised to ask a pharmacist for advice or contact NHS Direct on 0845 4647, stay at home and go to bed and drink plenty of fluids.

If people are in vulnerable groups or become increasingly unwell, with vomiting, diarrhoea, or breathing problems, they should seek medical advice.