For nearly twenty years, I’ve been in a toxic and dependent relationship with Shapewear.

We break up, I swear it’s over and then, weeks later, a special occasion comes along and I go running back, sucked in by promises of a lifted bottom, flattened tummy and dropping a dress size.

These days, shapewear isn’t confined to what we wear beneath our clothes, either. What is the latest fashion obsession? These jeans promise to be as stretchy and comfortable as a muffin top.

We all happily tossing our jeans in the closet during lockdown and swapping for blissfully comfy loungewear.

Contour jeans, £25, F&F at next.co.uk Stretch denim with a mid-rise fit. MODEL ELEANOR says: ¿The denim feels cheap and scratchy, and they flatten my bum, rather than lift

Contour jeans, £25, F&F at next.co.uk This stretch denim is cut in a medium-rise style. MODEL ELEANOR says: ‘The denim feels cheap and scratchy, and they flatten my bum, rather than lift

Bum Sculpt Skinny jeans, £46, riverisland.com Innovative stretch denim that sculpts. ELENAOR says: ¿I normally avoid the skinny profile but these flattered me.¿

Bum Sculpt Skinny jeans, £46, riverisland.comInnovative stretch denim, that shapes. ELENAOR says: ‘I normally avoid the skinny profile but these flattered me.’

High Rise Sculpt True Skinny jeans, £54.95, gap.co.uk Stretch denim cut to sit above the hips. ELENAOR says: ¿The jeans are comfortable and slimmed my waist right down.¿

High Rise Sculpt True Skinny jeans, £54.95, gap.co.uk Stretch denim cut to sit above the hips. ELENAOR says: ‘The jeans are comfortable and slimmed my waist right down.’

But now, as life gets back to normal, we’ve been dusting them down and — if you’re anything like me — finding our old ones no longer fit.

No wonder Marks & Spencer has seen a boom in jeans sales.

In the last six months, more than 2 million of its Magic Shaping Jeans have been sold. These jeans promise to lift the bottom and reduce spare tire wear.

My problem with shapewear is that the flab doesn’t just disappear — it has to go somewhere. I have found that it is more likely to reappear if it’s pushed down one way.

Anybody who’s ever tried to blow up a mattress will know what I mean. Even if it does knock off a few inches and give you a slim silhouette, you can’t go anywhere, as the shapewear is so tight you walk like a zombie and sitting is impossible.

High Waisted Lift & Sculpt Skinny jeans, from £75, landsend.co.uk Stretch denim with a ¿no gap¿ waist. ELENAOR says: ¿These gave me a fabulous pert bottom.¿

High Waisted Lift & Sculpt Skinny jeans, from £75, landsend.co.uk Stretch denim with a ‘no gap’ waist. ELENAOR says: ‘These gave me a fabulous pert bottom.’

But perhaps the latest models have got a little more ‘give’ to accommodate wobbly bits?

We decided to put them to the test — by trying all the jeans on a size 16 model.

We measured her waist in normal jeans — 38.5 inches — then compared that to the measurement of each slimming pair.

Comfort is the most important thing. When I hold up a £39.50 pair of M&S Magic Shaping Straight Leg jeans (third from right) in size 16, they look so tiny that I have to double-check the label.

It will take magic to make these happen, but not magic.

Flared jeans, £130, next.co.uk The Gut Check panel targets the tummy. ELENAOR says: ¿They definitely suck you in, but you couldn¿t sit comfortably for long in them, let alone eat!

Flared jeans, £130, next.co.uk The Gut Check Panel targets the stomach. ELENAOR says: ‘They definitely suck you in, but you couldn’t sit comfortably for long in them, let alone eat!

Marks & Spencer tells me the jeans are made using ‘clever technology’ and ‘shaping darts’ but, let’s be honest, it’s just super-stretchy fabric.

It is a miracle that they fit. They’re soft, comfortable and my saggy bottom looks plumped up and lifted.

The waistband, although Simon Cowell-high, has helped to reduce my stomach.

The sitting down test is also easy for them. Although I expected the flab would explode, it remains nicely contained.

Magic Shaping Straight Leg jeans, £39.50, marksandspencer.com Shaping darts offer an extra lift. ELENAOR says: ¿My favourites! They slim down my figure well.¿

Magic Shaping Straight Leg jeans, £39.50, marksandspencer.com The addition of shap darts gives you an additional lift. ELENAOR says: ‘My favourites! They slim down my figure well.’

Florence Skinny Mid Rise Instasculpt jeans, £184, iris fashion.co.uk Sustainable contouring jeans. ELENAOR says: ¿These are soft and give you a good hourglass shape.¿

Florence Skinny Mid Rise Instasculpt jeans, £184, iris fashion.co.uk Sustainable contouring jeans. ELENAOR says: ‘These are soft and give you a good hourglass shape.’

It’s a different story when I try on other size 16 shaping jeans. A £130 pair made by Spanx, trailblazers of the shapewear world (fourth from right), may feature a delightful-sounding Gut Check panel, but they’re so tight and thin that it’s like wearing denim tights. The more affordable F&F Contour jeans (far left), costing £25, are so high-waisted that they virtually sit under my armpits, even if they do slim my thighs.

Gap now sells jeans online. I try a pair of its Sculpt jeans for £54.95 (third from left). They have ‘hidden holds-you-in front pockets that help give you a sleek, smooth look all day’.

However, I’m delighted when a size 16 is way too baggy for me. For a brief moment I wonder if my fat was pushed in so far by the M&S jeans that it’s vanished for ever. This would really be magic.

Rocket Galaxy jeans, £260, irisfashion.co.uk Uses a sculpting weaving technique. ELENAOR says: ¿These are very tight. I¿d also never pay this much for jeans.¿

Rocket Galaxy jeans, £260, irisfashion.co.uk This technique uses sculpting weaving. ELENAOR says: ‘These are very tight. I’d also never pay this much for jeans.’