Public health chiefs are urging people to 'regularly wash your hands, maintain social distancing and to continue to stay at home as much as possible' after four Dorset schools have reported positive coronavirus cases within days of opening to pupils.

St Mark’s CE Primary in Swanage and Yewstock School, a special school in Sturminster Newton, are both completely closed to all pupils. Merley First School near Wimborne and The Gryphon School in Sherborne remain open but some pupils and staff have been sent home to self-isolate as a precaution.

News of the positive cases in schools comes as the government announced social gatherings of more than six people will be illegal in England from next Monday. The law change will ban larger groups meeting anywhere socially indoors or outdoors.

At St Marks Primary a single staff member tested positive after being on the school premises at the end of last week. However, after consulting with Public Health England South West, several other staff members were asked to self-isolate for 14 days.

The school says because it is small they have no option but to close. A Year 13 pupil at The Gryphon School tested positive and is now self-isolating, as are students and staff who have been in close contact with the individual.

Yewstock School - which caters for children aged between two and 19 with severe, complex or moderate learning difficulties - is now undergoing a deep clean, meaning classrooms are closed to all pupils and staff.

Staff that came into close contact with the member of staff who tested positive for the virus have been encouraged to self-isolate for 14 days and get tested.

Reception children have been forced to stay away from class after a confirmed case of coronavirus at Merley First School. The case was confirmed on Tuesday afternoon after a group of Reception pupils and parents visited the Reception classroom for an hour on Monday.

Sam Crowe, Director of Public Health for Dorset and BCP Councils, said “Public Health England and the school have completed a risk assessment, and we are taking all necessary measures to make sure we minimise the risk of any transmission in the school.

“The school (St Mark's) has been working closely with PHE and ourselves and this is being managed appropriately. We will support the school as they provide home learning to the pupils and we will continue to provide advice and guidance to ensure high standards of hygiene and social distancing are maintained.

“It is important everyone self-isolating adheres to the government guidance; if they don’t have symptoms they do not need to get a test.

"However if a member of their household has symptoms and takes a test then they should self-isolate.

“I would like to remind all our schools and the wider community that the best way to prevent the spread of the virus is to regularly wash your hands, maintain social distancing and to continue to stay at home as much as possible.

“If you do start to develop coronavirus symptoms, such as a new continuous cough, a high temperature or a loss or change to your sense of taste or smell, please self-isolate and book a test.

“We would like to reassure people living and working in Dorset that while we do expect to see more cases in the weeks and months ahead, we have robust mechanisms in place to contain the infection and protect the health of the local community.”

Schools were forced to close as part of the national lockdown on March 20, and only started reopening their doors over the past few days.

Dozens of schools have been affected by positive coronavirus cases nationally.

A Department for Education spokesman said: “The very small number of schools that are asking some or all of their pupils to remain at home are following our clear published process following a positive case being confirmed in a school. If a positive case is confirmed, swift action will be taken to ask those who have been in close contact with them to self-isolate, and Public Health England’s local health protections teams are standing ready to support and advise schools in this situation. Children who are self-isolating will continue to receive remote education from home. We will continue to work with schools to ensure all appropriate steps are taken to keep pupils and staff safe.”