A day nursery is threatening to sue a healthcare regulator after it was criticised in a report for staging a birthday party where staff members covered each other’s bodies in cream and licked it off.

The community health service (GGD) in Utrecht said the party at Kinderdagverblijf Jolie was inappropriate because it took place at 10am, while children were in the building.

But in a written objection to the city council, financial manager Piet Bais insisted that the party to celebrate a colleague’s 50th birthday had been held out of sight of the children. ‘It was in a closed-off area where children could not come in or look in,’ he said.

During the party colleagues covered the woman whose birthday was being celebrated in silver foil and then sprayed cream over her before licking it off. A male staff member then took off his shirt in what Bais described in a letter to parents explaining the situation as an ‘outburst of spontaneity’.

The GGD launched an investigation after receiving an anonymous tip-off about a ‘striptease’. Bais called the suggestion ‘defamatory and threatening’ and said the nursery was considering going to court to force the council to identify the whistleblower.

Bais said nobody at the nursery objected at the time and described the staff member who was celebrating her birthday as somebody ‘who likes a bit of attention from men’.

Utrecht city council said it had ordered the nursery to inform parents about the incident and confirmed that the organisation’s written objection was being processed.