New research claims to show how the position you sleep in with your partner can reveal the strength of your relationship.

The key is the distance between couples, according to the study of 1,100 people, which was published today at the Edinburgh International Science Festival.

The study, which expands on work by psychiatrist Samuel Dunkell, claims that partners who sleep less than an inch apart are far more likely to be happy together than those maintaining a gap wider than 30 inches.

The study says that people who lie curled up in the ‘full foetal’ position are likely to be indecisive, anxious and sensitive to criticism from their partner.

Those who sleep in a ‘semi-foetal’ position, with their knees drawn up, are amenable to compromise with their other half, and unlikely to take extreme stances, the study said.

People who sleep in the ‘royal’ position – flat on their back – tend to be confident, open, expansive, and sensation-seeking when it comes to their love life, the study said.

The study claimed that those who lie on their face show a tendency for rigidity and perfectionism, which can lead to problems in a relationship.

Apparently couples tend to be happier if they fall asleep face-to-face than if they ‘spoon’ their partners, facing the same direction, or if they face in opposite directions.