At 1pm on Monday, a family van parked outside the Science Museum in central London. Within two hours, as the family of four including eight-year-old Lucas and his younger sister Emilea returned from the nearby Natural History Museum, they found their windows had been smashed.

There must have been a burglary, they thought; in fact, as they found later, their vehicle had been at the centre of a major security alert involving the bomb squad. Counter-terrorism police had evacuated the museum and closed roads before breaking into the van, suspecting it contained a bomb. Instead, they found dolls and stationery scattered around inside.

Cristian Ivan, the Romanian father, had no idea the big “Iran is Great” sign emblazoned on both sides of his van could cause such a commotion.

Cristian, his French wife, Audrey, and German-born children had arrived a week earlier to participate in a festival in Wales, their first visit to the UK. In the five years since they started to live and travel in their van around the world, visiting museums has become an essential part of the home schooling of their kids. It was during a trip to Iran that they fell in love with the country and later decided to start their own campaign encouraging others to visit.

“Visiting museums is like school for our children,” Cristian said. “We parked the car in front of the Science Museum; when we came out we were confused – why would the police do something like that? We were told it was because of the message written on the van.”