The study has found that three quarters of females become suspicious when their husband turns up out-of-the-blue clutching flowers -- they think it is a sign that her man is cheating on her.

A box of chocolates usually suggested he had lied about something and a candlelit dinner often meant he has bad news. However, the gifts that don't cause suspicion are treats such as cakes or a takeaway, it found.

Researchers asked 1,500 men and 1,500 women in long- term relationships what they thought about presents from their partners and found the level of suspicion is related to the cost of the gift, the 'Daily Mail' reported.

"You might have the best intentions, but buying your partner a surprise gift can get you in hot water. The more indulgent the gift, the greater the suspicion it seems.

"The common misconception is that only cheats treat their partners with expensive gifts, so if you want to sweet talk your partner the best way to say it is with a piece of cake," Graeme Nash, of Greggs the bakers, which commissioned the research, was quoted as saying.

Nearly half of the men said they had stopped buying gifts for a partner in the past in case it lead to paranoia. And more than a quarter of women said their partner had given them a gift in the past after doing something wrong.

On average men treated their partners to three surprise gifts every year. Men should stick to buying cakes and takeaways as they are the only gifts guaranteed not to spark suspicion, the study found.

A woman's level of suspicion also rises in proportion to the cost of the gift, it revealed.