London (CNN) -- British Prime Minister David Cameron thought his daughter Nancy was with her mom. Her mom, Samantha, thought the 8-year-old was with her dad.

In fact, they had left her behind at a pub about a mile from the prime minister's country residence, staff at the pub said.

"The prime minister and Samantha were distraught when they realized Nancy wasn't with them," Cameron's office said in a statement Monday. "Thankfully when they phoned the pub -- she was there safe and well. The prime minister went down straight away to get her."

The incident happened "a couple of months ago," said a bartender at the Plough at Cadsden who declined to give his name.

It was reported widely in the British press Monday.

Cameron and his wife left the pub in separate cars, and each assumed Nancy was with the other one, the Press Association said.

Nancy was helping pub staff when her dad came back to get her about 15 minutes after he left, PA reported.