Seeing red at the Serpentine Pavilion

What a scorcher the weekend proved to be. It was far too hot in our airless rooftop eerie, with humidity and searing temperatures that made Tenko look like it was set in Reykjavik.

So what better way to cool off than a paddle around Hyde Park's Diana Memorial Fountain? Although much maligned upon its opening (an inevitable fate as nothing was ever going to be good enough for the tabloids) the bubbling stream is a pleasurable way to cool off overheated tootsies, even when it is filled with marauding children. It's a lot safer now the grey granite surface has been etched to provide some grip for bare feet, although with its sharply incised gullies and sudden protuberances it remains pleasingly treacherous. 

The fountain itself is quite beautiful, the effect marred not only by all the people gawping and dipping their toes, but also the asphalt path that winds across it. With the right setting it could be so much more special, a bit like Thomas Heatherwick's East Beach Café in Littlehampton that looks less like driftwood on the beach and more like a dog turd in a car park.

Back to Diana (I'm beginning to feel like the Daily Express). Much fun can be had trying to spot the metaphors in the design. Does that footbridge represent a Parisian underpass? Do those swirling rapids echo her inner torment about Camilla? It's almost as much fun as the deeply moving Diana and Dodi memorial in Harrods, which never fails to bring a tear to my eye. 

Anyway, the main aim of the day was to experience this year's Serpentine Pavilion. Designed by Jean Nouvel, this year's structure is the 10th commission in the annual series. And like most years before, this overhyped café and auditorium managed to deeply disappoint. The only thing more disenchanting is the exhibition programme at the adjacent Serpentine Gallery. Time spent viewing Wolfgang Tillmans: Three minutes (including one minute for politeness, as it was felt rather rude to leave so hastily). 

The Pavilion is a depressing space, fabricated entirely from red materials. On a hot day, the café interior is an extremely uncomfortable environment, the overwhelming ruby colour scheme makes the space feel angst-ridden. Not a place to linger over a cup of Earl Grey and slice of lemon cake.

This year's effort feels particularly cheap. However, there are moments of delight: the main statement is an inclined red wall clad with red polycarbonate panels, which catches the sun and contrasts with the surrounding trees. Undoubtedly the pavilion incorporates elements that photograph well, making it ideal fodder for architectural magazines. But as a place to visit, linger and relish? No thanks.

Nouvel has created some incredible buildings, but seems determined to drag London down. His design for One New Change in the City, currently nearing completion, is another gloomfest, with its drab angular facades. Located across the road from St Paul's, this "breathtaking monument to modernism" is like the gloomy guest at a party who brings everyone else down.