A mysterious message which sparked bafflement when it was spotted in an Oxfordshire field has been revealed as the handiwork of a "grumpy" farmer.

Social media was awash with speculation after a police helicopter saw the letters "SUE x" etched in huge letters on a field in Tetsworth, near Thame.

The National Police Air Service wrote alongside the image: "Does anyone know Sue just south of #Tetsworth, the other side of the M40?! #WhoIsSue #p1526"

In a subsequent tweet, the service encouraged internet users to share the message "far and wide".

Conspiracy theories soon began to cascade, including suggestions it was an iPhone X advertising campaign or even an alien invasion.

But the reality was more prosaic.

Farmer George Graham had created the message for his wife - Sue - to apologise for being moody.

He employed a GPS-operated tractor to spray the crops in the shape of her name, the BBC reported.

He told BBC Radio Oxford: "I'm not quite as grumpy and old as perhaps I make out occasionally."

The farmer added: "As ever, everything has its ups and downs, so I thought I'd try and make a gesture at some point, and that was the one I chose."

According to his son, Mr Graham had been in his wife's bad books for not "pulling his weight" around the house.