It could have been another stain on what is proving to be something of an 'annus horribilis' for Spain’s royal family.

This time it's King Juan Carlos’s eldest daughter Elena who appeared to have landed herself into trouble.

According to a Spanish Civil Guard Police fine, the 49-year-old Spanish princess was all set to pay Spain's Directorate of Traffic between €601 and €3,005 for driving a tractor in the municipality of Gaeria without the appropriate licence.

Surely no royal would get behind the wheel of a farm vehicle, you may ask.

Whether Elena is a fan of tractors isn't common knowledge, but she definitely wasn't driving the one which the fine corresponds to.

It’s all down to a mistake by the two Valladolid Civil Guard officers who wrote up the fine.

According to local daily El Día de Valladolid, one of the officers told the other not to bother writing the driver’s ID number and only jot down the vehicle’s registration number.

But the number 12 was already down on paper, which corresponds only to Infanta Elena’s identification number.

And thus the Spanish king's eldest daughter was sent a hefty fine of between €601 and €3,005, even though the mistake has since been recognized.

Spanish IDs usually have eight numbers and a letter, but Spain’s royal family have only two.

King Juan Carlos has number 10, Infanta Cristina has number 14, Prince Felipe has number 15 and nobody has 13 for superstitious reasons.

If you’re wondering who number one corresponds to, it was none other than Spanish dictator Francisco Franco.