When it was opened in 1881, pretty much everyone hated the Natural History Museum.

That ornate gothic style was just slightly out of date. In the same way that going to the Wolseley in a pair of Joan Collins Dynasty shoulder pads would be slightly out of date today. And just as risible.

The thing is, though, that now absolutely everyone loves the place and the person who loves it most of all is me.

I know it’s more gaudy than Paris Hilton’s knicker drawer and I know it’s full of ecologist schoolteachers telling groups of disinterested children that unless they stab their gas-guzzling parents all animals will end up as bones in glass boxes in there.

But my oh my . . . what a temple, what ambition, what detailing!

Paid for with money generated from the Great Exhibition, the Natural History Museum is like all the world’s best cathedrals. It’s much more interesting to look at than anything that’s going on inside it. It is brilliant, and every time I come into London on the M4 I fervently wish for a traffic jam on the Cromwell Road just so that I can spend a little more time drinking it all in.

And naturally this brings me on to the boot lid of the 7-series BMW.

There was a problem with it from the start. You see, BMW had employed an American stylist by the name of Chris Bangle, who had a beard and a not-bad CV from Fiat, where he’d done the 1990s Fiat Coupé. Not a bad-looking car in many ways, except that Chris had given it four eyebrows.

Anyway, Johnny Yank had arrived at BMW determined to breathe some new life into the brand, which – until that point – had stuck very rigidly to the principle that all cars should be styled with nothing more than a sturdy 2HB pencil and a ruler.

His first attempt was the 7-series, and it was a complete disaster, chiefly because he’d fitted a boot lid and then left it in the oven for too long. So it had melted and sort of dribbled down over the rear valance.

Horrified by slow sales of this unlovely monster, BMW quickly ordered a redesign. But Chris mucked this one up as well. And the one that followed shortly thereafter.

And by this stage he’d set to work ruining the 6-series too – a job he completed spectacularly well. This one had an even bigger, even more melted boot lid, which, if you squinted, looked like a forgotten soufflé. In the meantime he was starting work on a sports car called the Z4. It was imperative that this car should look good, because good looks are the raison d’être for cars of this type. But I’m afraid he made a complete hash of it.

And then, to make matters worse, he came up with a trendy designer handle for what he was doing, calling it “flame surfacing”.

Others called it “bollocks”. The designer J Mays at Ford laughed openly, while Marc Newson, an industrial designer, said the Z4 appeared to have been designed with a machete. Meanwhile, Renault’s stylist, Patrick Le Quement, politely described it as “hollow”.

And as for me? Well, I’m sorry, but Bangle said that his influence for the Z4 was the Guggenheim museum in Bilbao.

I see. So you modelled a car on what looks like an aircraft carrier that has crashed into a city. Wouldn’t it have been better to maybe use a shark, or perhaps a tiger as your starting point? Just a thought.

Sadly, Chris wasn’t listening. He was busy working on the new 5-series – his absolute worst effort so far, with headlamps like Dame Edna Everage’s spectacles and lines that make no sense at all.

Then, after the 1-series came out looking like a severely kicked-in bread van, BMW had plainly had enough, so it booted its American whiz-kid upstairs, where he could do less harm.

And that’s a pity, because it was at this exact moment that I realised that the “flame-surfaced” Z4 is just as striking and wonderful as the building that inspired it; and that the 6-series is in fact perfectly balanced and gorgeous; and that the 5-series – when it has the right wheels on – makes the rival models from Audi and Mercedes-Benz look as dumpy and lumpy as phlebitis.

And that brings us on to the BMW 3-series. Frightened that any more mad Banglism might scare away buyers of the cash cow, the company high-ups insisted that this model should be a fairly normal-looking affair.

And so it turned out to be. Fairly normal. And as boring as a bucket of wallpaper paste.

This is a car you would buy like you would curtain material – by the foot.

“Yes, I’d like 15ft of car please.” “Certainly, sir. How about a 3-series?” It is a magnolia bathroom suite. It is beige paint. It is biscuit carpeting. And worst of all, from the back it looks like a Kia.

In a BMW showroom full of Bangle’s brilliant early works, it sticks out like an art school doodle in the Tate Modern’s engine room.

And the convertible is worse. As is the norm these days, the convertible roof is made from metal, and that’s just fine. But to stow such a large lump of ironmongery, and the rear window, the boot has to be as big – and as stylish – as a Korean grain carrier.

To make matters worse the model I tested was the big-engined 335i, which is all yours – fitted with a few necessary extras – for a whopping £46,000 (though a basic model costs £38,035).

Make no mistake, this is not a bad car. No, the manual gearbox is not completely precise, and yes, there is a whisper of wind noise from the point where the roof meets the windscreen, but this is only audible on the M26 motorway at 7pm, when you have a 7.50pm flight to catch from Gatwick . . .

Of more interest is the twin-turbo motor. This is a straight-six and any engineer will tell you that this is the smoothest cylinder configuration you can have for an engine. He will also tell you – if you don’t punch him in time – why that is.

But in this BMW it isn’t smooth. In fact on tickover it rumbles and judders like a big American V8, and I think they may have done this on purpose by messing with the crankshaft or the firing order. Maybe they wanted to give it some character, and if that’s the case it’s worked – I liked it a lot.

As you’d expect, it’s a dream to drive on really good roads. When the going is empty, all BMWs feel balanced and neutral, and while they may not all be as fast as the “ultimate driving machine” tag would have you believe, the 335i Convertible . . . er . . . is. Especially when you’re really, really late for a plane.

In sixth gear it will accelerate even faster than the old M3 would, but it won’t shake your head off in the process. Yes, the ride is firm, but it’s bearable.

And while we’re on the subject of comfort, full marks – plus a star – for all the oddment stowage space they’ve provided in the cabin. It’s especially useful in a convertible, and doubly especially useful when the boot, despite outward appearances, really isn’t that big at all.

But I’m sorry, we have to go back to that price tag. At £46,000 it is dangerously close to the Audi RS4 Cabriolet, and probably not that far behind what one of the new soft-top M3s will cost.

And I’m sorry again, but anyone with a 335i is going to spend his entire life explaining to colleagues why he didn’t go the extra mile and get the big boy instead.

It will be particularly painful when the time comes to sell. M3s on the secondhand market are always fairly cheap, so to make your 335i look attractive you’ll have to sell it on for mere pennies.

And even that might not do the trick, because of the way it looks. I stand corrected with other BMW models. But with the 3-series, I’m sorry.

It’s not the Natural History Museum or the Trellick Tower, and it never will be. It is, I’m afraid, Coventry Cathedral. A turd that even time cannot succeed in polishing.

Vital statistics

Model BMW 335i SE Convertible

Engine 2979cc, six cylinders

Power 302bhp @ 5800rpm

Torque 295lb ft @ 1300rpm

Transmission Six-speed manual

Fuel 28.5mpg (combined cycle)

CO2 238g/km

Acceleration 0-62mph: 5.8sec

Top speed 155mph

Price £45,750

Rating

Verdict As boring as wallpaper paste

Explore Jeremy Clarkson

• Greatest Hits

• Good Car, Bad Car