The most popular sleeping positions for British couples have been uncovered by a survey for hotel chain Travelodge.
Psychologists suggest changes could be a cause for concern
The sleep behaviour poll suggests the most popular position is sleeping back-to-back but not touching.
Some 27% of couples are said to adopt the so-called liberty pose, with the second most popular position - cited by 23% - being back-to-back but touching.
The survey of some 2,000 people also found 92% of couples stick to the same side of the bed each night.
Travelodge found "spooning" with the man on the outside was adopted by 20% of couples while some 8% slept in the position with the woman on the outside.
The lovers' knot - where couples face each other, legs intertwined for about 10 minutes before separating to sleep - was favoured by 10%.
But just 2% of respondents said they opted for the position without separating before going to sleep.
The romantic - a favourite in Hollywood films in which the woman lies with her head and arm on a man's chest - was named by 4%.
According to relationship psychologist Corinne Sweet, the most popular liberty pose means a couple feels connected but independent enough to sleep separately.
The second most popular, the cherish position of being back-to-back but touching, is a favourite in new relationships and shows a couple are comfortable, intimate and relaxed with each other, said Ms Sweet.
She said the lovers' knot can be taken as a demonstration of intimacy and sexual activity.
Ms Sweet said: "Couples fall into habitual ways of sleeping together that suits their personalities and personal preferences.
"These are negotiated at the outset, so if something changes in how they sleep together, this can reflect a change in their relationship and cause concern for the other partner."