A three-month old baby has been hauled in for questioning by the US embassy in London after his grandfather accidentally marked him as a spy, terrorist or war criminal, the UK’s Guardian newspaper has reported.

When applying online for a visa waiver through the country’s ESTA travel system, Grandfather Paul Kenyon mistakenly clicked ‘yes’ on the question: “Do you seek to engage in or have you ever engaged in terrorist activities, espionage, sabotage, or genocide?”

“I couldn’t believe that they couldn’t see it was a genuine mistake, and that a three-month-old baby would be no harm to anyone,” Mr Kenyon told The Guardian.

When travel was refused, the family was asked to attend a visa interview in America’s London embassy – 300 km from the family’s house in Cheshire.

The child’s parents missed their flights and had to delay their trip, the error costing the family around $5000.

Mr Kenyon said while he could see the funny side, officials at the US embassy appeared to have no sense of humour about the situation.

“He’s obviously never engaged in genocide, or espionage, but he has sabotaged quite a few nappies in his time, though I didn’t tell them that at the US embassy,” he told The Guardian.