Nervous suspects  locked up in Britain's newest police station may feel relieved by a pleasant yellow Colour on the door. If they are close to confessing a crime, the blue on the wall might tip the balance.     Gwent Police have abandoned colours such as greys and browns of the 20th-century police cell  and have used colour psychology to decorate them.      Ystrad Mynach station, which recently opened at a cost ofPS5 million, has four cells with glass doors for prisoners who suffer from claustrophobia . Designers have painted the frames yellow, which researchers say is a calming colour. Other cells contain a royal blue line because psychologists believe that the colour is likely to encourage truthfulness.      The station has 31 cells, including 12 with a "live scan" system for drunken or disturbed prisoners, which detects the rise and fall of their chest. An alarm alerts officers if a prisoner's breathing stops and carries on ringing until the door is opened.     Designers and psychologists have worked for years on colour. Blue is said to suggest trust, efficiency, duty, logic, coolness, thinking and calm. It also suggests coldness and unfriendliness. It is thought that strong blues will stimulate clear thought and lighter, soft colours will calm the mind and aid concentration.     Yellow is linked with confidence, self-respect and friendliness. Get the colour wrong and it could cause fear, depression and anxiety, but the right yellow can lift spirits and self-respect.     Ingrid Collins, a psychologist who specializes in the effects of colour, said that colour was an "energy force". She said: "Blue does enhance communication but I am not sure it would enhance truthful communication."     Yellow, she said, affected the mind. Red, on the other hand, should never be considered because it could increase aggression. Mrs Collins praised the designers for using colours in the cells. Gwent is not the first British force to experiment with colour to calm down or persuade prisoners to co-operate. In the 1990s Strathclyde Police used pink in cells based on research carried out by the US Navy. Which of the following colours should NOT be used in cells according to me passage?
Pink. Yellow Blue. Red.