Did the Duchess of Cambridge reveal she's expecting a daughter?PA

It was only a slipped syllable, but in uttering it the well-spoken Duchess of Cambridge may have revealed the gender of her unborn baby – and it's a girl! Possibly.

The media are all a flutter this morning with speculation that Kate Middleton's slip of the tongue has let the nation know what only she, husband William and a handful of doctors should.

For during a walkabout yesterday, one member of the crowd overheard her say the 'D' word, which in this context can only mean 'daughter'.

Sandra Cook, 67, who was among the 2,000 wellwishers who greeted the Duchess on her visit to Grimsby, said: "The lady next to me gave her a teddy bear and I distinctly heard her say 'Thank you, I will take that for my d....'. "Then she stopped herself.

"I leant over and said to her: 'You were going to say daughter, weren't you?' She said: 'No, we don't know!' I said: 'Oh, I think you do' to which she replied: 'We're not telling!'"

Diana Burton, 41, who gave Kate the teddy, was too star-struck to recall the conversation. But Sandra, who works in a local charity shop and lives in Grimsby, was adamant about what she heard.

"I only hope that she doesn't now give birth to a boy or I'm going to look pretty stupid,' she said. But she definitely said 'd------'."

There was more baby talk and plenty of gifts for Kate as she went on a 10-minute walkabout outside the National Fishing Heritage Centre.

One admirer, Bobbie Brown, 42, asked Kate whether she had felt the baby kicking yet. She recalled: "She said: 'Yes it is, very much so'."

Is Kate expecting a daughter? Or did she just have a blocked nose and meant to say 'boy'?