Prince Harry and Meghan Markle have condemned two photographers as extraordinarily reckless after they were spotted walking the perimeter of the UK school attended by Prince Archie and Princess Lilibet, stopping to look into the grounds.

The men were identified by police as international photographers working for a European press agency who had arrived in a rented white van. The couple called the episode an unacceptable intrusion into the privacy of children, saying the photographers had walked the full perimeter of the school and paused to peer into the grounds where pupils were going about their day.

The incident came only days after a separate security scare near RAF Fairford, and has sharpened the couple's concerns about the safety of their children since the family's return to the UK. Harry and Meghan's children, who are the King's grandchildren, have been at the centre of long-running disputes over the family's security arrangements, and each new incident adds weight to the couple's argument that the threat they face is real and persistent.

The couple's statement was notably blunt. They said the photographers' behaviour went far beyond legitimate news gathering, describing it as an extraordinary level of recklessness that no parent should have to tolerate. The fact that the men were identified as working for an international agency, rather than British outlets, has raised questions about how press intrusion is regulated when it crosses borders and about the responsibilities of agencies that sell images into the global market.

Royal children have long been a flashpoint in the debate between press freedom and privacy. Successive generations of the royal family have sought to give their children as normal a school life as possible, and incidents involving photographers at schools have repeatedly prompted calls for stronger protections. Editors' codes in the UK contain specific provisions about photographing children, but enforcement against foreign operators is widely seen as difficult.

Police are understood to have taken details of the men and the van, though no arrests have been reported. The Sussexes have made clear they will continue to challenge what they see as dangerous media intrusion, particularly where their children are concerned. The episode is likely to feed into the wider and increasingly heated debate about the safety of public figures' families, and about where the line sits between the public's interest and a child's right to be left alone.

The Sussexes' relationship with the media has been adversarial for years, and the couple have repeatedly said that intrusive press behaviour poses a genuine safety risk to their family. Their UK visits are typically low-key, and each reported incident is documented by their team. Whether the latest episode leads to formal complaints to regulators or to the agency involved remains to be seen, but the couple have shown no reluctance to pursue such cases through the courts in the past.