ARE you tubby?

Perhaps a little more rotund than you would like? Well, sorry, you've no-one to blame but yourself – at least if Joanna Lumley is to be believed. "Lots of people nowadays are too greedy," the actress said last week. "People think: 'I must have a cupcake.' What do you mean you must? You'll get fat, you fool."

That resounding clang was the sound of copious biscuit tins hitting the floor.

I have to admit my own jaw fell, but thankfully recovered in time so as not to spill a drop of the family-sized trifle I was ladling into my mouth.

Still it raises the question: why is the Government spending millions of pounds on public health campaigns when Lumley could have solved the obesity crisis single-handedly? She did save the Gurkhas. Why didn't we go to her sooner?

Frankly, she's speaking out of the proverbial rear end. Sure, there are those whose choices – be it an excess of junk food or sedentary lifestyle – undeniably lie at the heart of the issue.

But for many people the reasons behind their overeating is far more complex than simply lack of willpower: low self-esteem, stress, depression, bereavement or trauma after a horrific event.

As someone who spent the best part of a decade clinically obese, few things annoy me more than body fascists who seem hell-bent on starting a war between the fatties, thinnies and the inbetweenies.

We come in all shapes and sizes. I'm not sure why this is so hard for some people to grasp.

But Lumley had some further dietary insight to impart. "On a typical day I eat lettuce, followed by some lettuce, with lettuce. I don't exercise at all," she said.

So lack of calories and no endorphins – no wonder she's talking rot.