Eamonn Holmes and his co-presenter wife Ruth Langsford were discussing the story of Italian magazine Chi's publication of the intimate photos when the front cover flashed up and filled the screen, but the pictures were not blacked-out.
Millions of people were able to see two pictures of the offending snaps as they were not blacked out. Eamonn was then forced to make a grovelling apology on air.
He said: "Unfortunately we accidentally showed an unblurred image of the magazine cover which briefly show the photographs.
"This was a regrettable error and the programme apologises unreservedly to the Duke and the Duchess."
Last night St James's Palace released a statement saying it was 'very disappointed' and that the publication of the pictures was 'a clear breach of the couple's right to privacy'.
Chi editor Alfonso Signorini told the BBC: "The photographs, which can in no way be considered scandalous, were bought from an international photo agency, do not harm the image of the protagonists and the reaction of the media seems to me wholly over the top.
"Moreover, the photographs can hardly be considered an invasion of privacy when the subjects are public figures in a public place, in the open air; specifically on a beach surrounded by other bathers."Another magazine, Australia's Woman's Day, has also published the photos of Kate but defended them - as well as those of Kate's sister Pippa - saying its readers will 'love' the images which are believed to have cost her magazine £30,000.
Speaking to Australia's Channel Nine network ahead of publishing the pictures in Monday's edition of the magazine, the magazine's editor, Fiona Connolly said: "This is not a hard decision about these photos. Kate's on a public beach, there are other holiday-makers there and she looks fabulous."
She made a distinction between the new pictures and those taken while Kate was topless on holiday in France last year as the latest ones were not taken at a private location.
Ms Connolly said: "Look, I think the British are very sensitive about this.
"As Australians, we see this every day. We see pregnant women in bikinis on the beach - and a public one at that - so we are a lot less sensitive here in Australia."
Reports say publishers in the United States, France and Germany have also bought the set for more than £100,000 in total. British newspapers and magazines have chosen not to publish the pictures out of respect for the pregnant duchess.
A royal spokesman said: "We are disappointed that photographs of the Duke and Duchess on a private holiday look likely to be published."