Prince Rock Primary School in Cattedown, Plymouth, had hoped to hold the event at nearby Tothill Park so parents could attend in line with Covid rules. However, six caravans arrived at the park on Tuesday night and still haven't be removed by the authorities.

       The school carried out a risk assessment but deemed the park unsuitable for use, Plymouth Live reports. Instead, the sports day will be held at the school playground this week and, as a result, parents won't be able to watch.

       Parents reacted in fury at the travellers.

       One wrote: "It's disgusting through those waste of spaces, the children have to have their sports day on their playground. Parents can't go now."

       Another posted: "The police should have more powers."

       The school, which caters for 390 pupils, communicated the news in a letter to parents this week.

       Headteacher Mrs Brake wrote: "Dear Parents,

       "It is with great regret that we have made the decision to move our sports day events to the school playground. This means that parents won’t be able to attend and we know this will be very disappointing for a lot of you. We will create some videos to share with you of the children enjoying their activities. All children should wear their sports kit tomorrow.

       "We have made this decision based on a few factors:

       "Not all of our year groups are in school this week due to a small number of children testing positive for COVID-19 and other children needing to self-isolate. This is not a situation unique to Prince Rock but is being experienced across the city and nationally.

       "Because of the self-isolation situation, we have staff who are not in school and this was making it increasingly difficult to have the ratios needed for an event off-site.

       "A group of travellers have moved onto the field next to the one we use. We have been in contact with Plymouth City Council about this and they have told us that more people are arriving today. We are, therefore, unsure what the situation will be with this tomorrow and our risk assessment suggests we should not use the public field.

       "Once again, we are sorry that you will not be able to attend. We are looking forward to next year when, hopefully, we will be able to enjoy a more normal year and welcome parents back to school events.

       "Please phone the school if you have any questions."

       Labour lost power of Plymouth City Council earlier this year to no overall political control.

       It owns Tothill Park, a large green space which boasts a tennis court, play area, bowling green and gardens.

       A spokesman for the council said: "We’re aware of an unauthorised encampment at Tothill Park and officers have visited the site on Tuesday morning to carry out welfare checks.

       "The possession that was granted to us after a previous encampment at this location still stands and so the encampment is being directed to leave."