Prisoners are having their cells painted pink to try to make inmates more cheerful.
Pink and other pastel shades are replacing traditional white
Five jails have taken part in the makeover programme which has seen traditional white or beige walls re-painted in a range of pale shades.
Leeds, Feltham, Wandsworth, Winchester and Eastwood Park, in Bristol, were selected for the pilot scheme which aims to cut suicide and self-harm in prisons.
The Prison Service and South Bank University, in London, used the refurbishment to look at the effect of colour on vulnerable prisoners.
It was found that pink and other light colours had a calming effect.
A Prison Service spokesman said: "A pilot study has been carried out to chart the effect of colour on vulnerable prisoners.
"Research indicates that colour plays a part in calming such prisoners."
It is not yet known wether the pasel shades will be repeated in other jails.