Mary Berry was left speechless when Alexander Armstrong shouted "motherf****" during a celebrity special of 'Pointless'.

Mary Berry

Mary Berry

The television host thinks he may have lost the respect of the baking queen forever after she heard him screech the offensive word for no reason when she appeared as a guest on an all-star special of the teatime show several years ago.

Speaking to the MailOnline, Alexander explained: "When we swear during filming, particularly when we have celebs on, it reminds them that we will edit it.

"That is when I decided to say 'Motherf*****' in front of Mary Berry. I don't think she visibly relaxed. I have seen her since and she has smiled. Perfectly genially."

His co-star Richard Osman, who is the question master, added: "She did not take that well and has not been back."

However, the 46-year-old host believes it's important to drop the odd expletive every now and then - except in front of the culinary goddess - because it helps the stars to relax.

He explained: "Sometimes the celebs are a bit prickly to start with. It takes a round or two to make them realise we're not having a laugh at their expense."

But the 81-year-old TV legend has made no secret of the fact she's never liked being in the company of potty-mouths.

Speaking to TV chef Gordon Ramsay in the past, she said: "I don't think there is any excuse. If the young are watching they'll think it's normal and they can do it."

Meanwhile, Mary is set to return to the next series of 'Great British Bake Off' later this year alongside Paul Hollywood.