Cowley Manor, Cowley

With a sublime spa and pool complex, chic Zen-like décor and inspirational gardens, Cowley Manor's food has a lot to live up to, says Tracey MacLeod

OK, I'll confess. When I was looking for a restaurant or hotel to suit this garden-themed issue, Cowley Manor caught my eye not so much for its notable gardens, as for the fact that those gardens contain a state-of-the-art modernist spa, with indoor and outdoor swimming pools.

OK, I'll confess. When I was looking for a restaurant or hotel to suit this garden-themed issue, Cowley Manor caught my eye not so much for its notable gardens, as for the fact that those gardens contain a state-of-the-art modernist spa, with indoor and outdoor swimming pools.

And what pools they are! In the glass-walled spa, there's a long, sleek beauty lined with dark-green Welsh slate. Outside, an infinity pool, its water held by a shimmering meniscus, steam pluming from its surface in the spring sunshine. Hang on. Where was I? Oh yes, the gardens. And the food.

Well, the gardens (Grade II* listed, and until recently under the care of gardening writer Noel Kingsbury) aspire to the condition of nature, reflecting the Victorian love for romantic wildness. They're not about pretty flowerbeds, but about semi-natural landscapes, and the interplay of stone and water, as the River Churn is tamed under bridges, into lakes, and through a magnificently thunderous Victorian cascade.

Lewis Carroll was said to have met the young Alice Liddell in Cowley Manor's gardens and there's a through-the-looking-glass experience in store for visitors today. They are greeted by the handsome, Italianate façade of a 19th-century mansion, standing in 55 acres of grounds. But inside, it's a funky Soho club, with a fabulous, Seventies-referencing design scheme, full of weird works of art and specially commissioned furniture and fabrics.

When it opened last year, the owners Jessica Sainsbury and husband Peter Frankopan aimed to create a rural bolthole for "hip urban professionals". They shrewdly spotted a gap in the market for a design-conscious younger clientele who wanted the kind of ambience and service they were used to in London. The chintz has emphatically been chucked out, along with all the other faux-rural clichés of the country-house hotel. Cowley Manor's bedrooms are from Japan by way of California, complete with top-of-the-range entertainment systems. The bathrooms are like mini spas, while the spa itself, in addition to those fantastic pools, boasts steam room, sauna, and a range of treatments to pamper every breed of exhausted yuppie.

A clever feature of the place is that despite its contemporary design, it still caters for the nostalgia of guests who like a bit of tradition from their mini breaks. So for Sunday lunch (served until 3pm) one could go modern, with grilled tuna, caperberries and tapenade, while another slipped back into Olde England, with roast beef and Yorkshire pudding (served on the side with its own jug of gravy). On fine days, lunch tables and Ron Arad chairs are set out on the large terrace, with views down to a limpid, frog-infested lake. And afterwards, for those who fancy a walk in the grounds, there are green Hunter wellies lined up to borrow. "We don't expect you to be the green-wellie-owning type," the line-up implies, "but you might get a kick out of camping it up in a pair of ours."

It's during the evening, though, that Cowley Manor's difference from the regular country house hotel is most conspicuous. Chilled informality rather than chilly formality is the order of the night, and the place becomes an urban playground for grown-ups. In the bar – sexily upholstered in low-slung black leather – the soundtrack is Jimi Hendrix rather than Vivaldi. Design mags and board games are supplied in the Claudio Silvestrin-furnished lounge. Or you can shoot pool on a blue table in a rock-and-roll leather-panelled room.

I've saved the food till last, because in truth, it doesn't match the rest of the place in terms of perfectionism and flair. In a reverse of the normal mini-break experience, where you put up with all sorts of knees-together gentility and soft-furnishing outrages for the sake of a great meal at the end of the day, dinner at Cowley Manor is of the standard you'd expect from a mid-range brasserie; they describe it as "unfussy and original" and it's certainly the first, if not the second.

There's no kitchen garden for the chef to plunder, but local meats are used for nostalgic comfort food like steak and kidney pie and braised shank of lamb, offered alongside the fancier fillet of seabass and breast of Gressingham duck. Of the dishes we sampled, the traditional seemed marginally more successful; the lamb shank had obviously benefited from long, slow cooking, falling unctuously from the bone, but was let down by a dry little cube of potato gratin. Wild mushroom and Parmesan soufflé needed stronger flavours to retain interest on the journey through its endless depths. Puds seem workmanlike, though christening one "squidgy chocolate pudding" seemed to be taking the nursery thing a little too far.

On weekdays the restaurant is open to non-residents, who can expect to pay around £30 for three courses, plus wine. A gawk at the décor and a stroll around the water features won't cost any extra. Sadly the most spectacular water features of all – those swimming pools – are only open to overnight guests. E

Cowley Manor, Cowley, near Cheltenham, Gloucestershire (01242 870900). Rooms from £205 to £395 per night