That's according to researchers from University College London – who claimed that when the rodents are shown an inaccessible food treat, they're likely to dream about how they can get it when they nod off to sleep.

Or as lead researcher Hugo Spiers put it: 'It's like looking at a holiday brochure for Greece the day before you go – that night you might dream about the pictures.'

The discovery was made by the team after they placed four rats at the bottom of a T-shaped pathway, where the animals could see the food but couldn't access it.

They were then encouraged to fall asleep in a nest – and their brain activity was recorded with 50 electrodes as they slept.

And after they were finally put back in the maze , the animals were seen to run along the arm of the T shape that had been previously blocked – which suggested that they had been carefully planning their strategy while in the land of nod.