AVENUE Q has been a phenomenon since its onslaught on Broadway over ten years ago, becoming one of the longest running shows on the US musical stage.

‘Sesame Street for adults’ is how the puppet-led musical is most often described, with the hilarious (and graphic) puppet sex scene in the first act certainly proof of its mature themes.

Relaunching for a UK tour after closing on the West End four years ago, the show, as you would expect, is still slick, well written and in places hugely funny.

But through no fault of the cast or crew at the Wycombe Swan last night, the 11-year-old musical is starting to show its age and suffers as a result.

Avenue Q follows the story of a group of residents on a suburban New York Street, each disillusioned with their unfulfilled dreams and the harsh realities of life.

It charts the arrival and travails of Princeton, a wet-behind-the-ears college graduate who finds out soon enough that life in his dorm was a far more cushy existence.

Focusing on the positives, the cast are excellent and there are star turns from Tom Steedon as Rod and the undoubted star of the show Lucie-Mae Sumner as the wonderfully sultry and perfectly named Lucy the Slut.

The songs are catchy, well sung and some leave you humming away into the summer night.

And director Cressida Carre has succeeded in getting her cast to plough themselves into the characters to the extent where you focus on the puppets, not the visible actors who animate them.

But outside of the hermetically sealed, puppeted world of Avenue Q, things have moved on.

While dealing with many universal themes, some of the issues discussed, or at least how they're handled, seem a little old hat to the extent where you wonder why there is a problem at all.

The storyline of Rod and Nicky, an almost direct port of the Muppets’ Bert and Ernie, revolves around Rod’s closest homosexuality.

But it remains a mystery why self confessed fan of musical theatre Rod puts up so much resistance to coming out while surrounded by a cast of compassionate, understanding friends urging him to do so, even if he is a Republican.

And while we are all aware of the plethora of pornography available on the internet, it hardly needs pointing out with its very own song as it may have done hilariously a decade ago.

The show is peppered with slight anachronisms like this, including the gift of a mixtape CD which to my knowledge was a fading reference even for the noughties.

And while there are plenty of belly laughs on offer in the first half, the second half is markedly free of the sort of humour you seem promised from the beginning.

What does still work is the pointed irony of a story depicting harsh realities through rose-tinted, Sesame Street spectacles of promise and juvenile dreaming.

However, a decade of risqué TV and musical theatre has overtaken the irrerevant scenes of Avenue Q and left them perhaps a little tepid.

Don’t get me wrong, there are great moments here, but anything it can do to try and shock has been blown out of the water by South Park, Family Guy or the Book of Mormon to the point where simple irony is just not enough for desensitised audiences.

But for all the references that miss the mark, some things will never change. Reflective ditty ‘The more you love them you more you want to kill them’ is proof enough of that.

And the writers perhaps captured it perfectly all those years ago with the closing lines - ‘except for death and tax, everything in life is only for now.’