Galleries and festivals are reinvigorating our coastline but do they bring lasting renewal?

Folkestone is one of those English seaside towns which, on a nice day, can lift the spirits but, in the drizzle, dampens them. Yes, it has a good-natured, rough-and-ready atmosphere, a working harbour, a sandy beach and a vestigial holiday industry; notably on a genteel, hotel-lined cliff top parade called The Leas. There is even a couple of new additions: a child-pleasing walk-through fountain and a brace of groovy glass-and-steel restaurants.

But there's no denying that elsewhere in Folkestone you'll find boarded-up shops and industries – ferries, fishing and holidays – that are in long-term decline. So when Roger De Haan sold his company Saga and started the Folkestone Triennial – a contemporary art festival which has just opened for its second run – he turned the salty town into one of the latest test-beds for art-led regeneration. As Peter Bettley of The Creative Foundation, which administers the Triennial, puts it: "The Triennial is about establishing Folkestone as a centre of contemporary art, assisting in its transformation."

The Folkestone model is not quite the same as the "Bilbao Effect", the shorthand for the Basque city's regeneration after the arrival of the iconic Guggenheim Museum in 1997.

"People were leaving Folkestone and not coming back," says Bettley. "Regeneration has to be embedded in the community, not imposed from above." Therefore, instead of a glitzy trophy, the Foundation has invested £40m in a "Creative Quarter" in Folkestone's historic centre, where it offers 80 refurbished properties on 125-year leases, available at affordable rents for start-ups and creative businesses. "It's not a property development as such, so will avoid what has happened elsewhere, with the likes of Starbucks moving in," says Bettley, adding that De Haan has another, more commercial 30-acre site at Folkestone harbour, master-planned by architect Terry Farrell.

Lucky old Folkestone to have such a cheerleader and another boost for the Kentish coast which, in April, saw Margate's Turner Contemporary centre open, itself pursuing the Bilbao Effect.

And while the regeneration boom of the 2000s may be easing up in the era of austerity, there are other recent openings – the Hepworth in Wakefield, Zaha Hadid's Riverside Museum in Glasgow, proving that there is life in arts-led regeneration.

Estate agents tend to like these projects, as they allow a bit of up-talking. "There's no doubt that there has been a positive 'Turner effect' in Margate, which was much needed," says Barnie Darby of Strutt and Parker's Canterbury office. "As agents, we're confident that the area will thrive and benefit from its new cultural identity. It's fast becoming a very popular area for families looking for a peaceful location and is considerably more affordable than more well-known places like Brighton."

It brings back the value that these resorts aonce enjoyed, says Andrew Harwood of Knight Frank in Tunbridge Wells. "For decades, much of the coast in Kent has been undervalued and there are signs that better times are returning to the Kentish coast, in particular Folkestone, Sandgate, Walmer and Deal."

And with good infrastructure: high-speed rail, the M20, the Channel Tunnel and a new ferry service about to be launched, it seems like a regeneration no-brainer. "I believe that cultural regeneration will have an impact on the property market in east Kent as these things 'lift' the area," says Janet Burnell of local developer Pentland Homes.

But will it work? For, in these sterner times, the arts-regeneration model is starting to unravel. "Firstly, much of the funding came with Labour and money isn't there any more," says Professor Loretta Lees of the Department of Geography, King's College, London. "Also, while some places work, others don't."

Arts regeneration, it seems, has become too widespread an orthodoxy. Indeed, Lees is part of a consortium working on a major research project for the Arts and Humanities Research Council, studying arts-led regeneration in the UK. From its research so far, she believes that there are some serious weaknesses in the model, which favours the middle-to-high income demographic at the expense of others. "The 'evidence' on arts-led regeneration is very poor in relation to socially-excluded communities and evaluations have been weak," says Lees. "A real problem is that there are few, if any, in-depth studies. Nonetheless, it is still the way that Government thinks."

Too many are still motivated by the Bilbao Effect and US academic Richard Florida's 2002 book The Rise of the Creative Class, which painted an irresistibly rosy equation of prosperity following the positioning of cultural and media industries in declining towns and cities.

Lees adds that there has been scant research into whether the effects of placing art into these communities are indeed beneficial and says that the measurements of success have been short-term and economically focused, rather than social. "I'd suggest that art-led regeneration has more often than not caused more art-led gentrification and the displacement of low-income groups," she says, arguing that this is what happened in Glasgow and Liverpool, following their City of Culture years. But while the idea has become questionable, there isn't a viable alternative to this 'state-led gentrification'. "Governments still see this model of urban regeneration as the only one out there – they seem unable to see any alternatives."

Equally, there is a significant layer of opinion within the cultural sphere that is uncomfortable about the instrumentalist agenda, constantly positioning art as a regenerative device. "I think that people are tired of culture being used as an agent of social change," says Stephen Snoddy, director of the New Art Gallery in Walsall. "People are fed up of politicians offering this up as a panacea."

Art galleries and festivals should address the local populations where they are situated and take responsibility for them, he says.

Lees' hunch is that art-led regeneration only works in areas which have a critical middle-to-high income population and although Margate comes with great expectations, she remains unconvinced of its long-term prognosis. "Margate hasn't got this middlebrow demographic and while the idea is that people will move there and use the new high-speed rail link to St Pancras, I personally doubt it," she says. "I was there recently and – while the Turner Contemporary looks great – I felt overwhelmed by the poverty of the population. I can't imagine that this flagship development will alter that economic reality."

Roger Hepher, head of planning and regeneration, Savills, points to a huge range of places that have tried their hand at the arts-regeneration game, from the Lowry Centre in Salford Quays, The Sage, Gateshead and of course, Tate Modern in Southbank: a somewhat forgotten district prior to the gallery's inception and an exemplar of its type.

Yet Hepher says that they can also be unsuccessful, with The Public arts centre in West Bromwich a case in point. "It was intended to bring something new to West Bromwich and act as a catalyst," says Hepher.

"But the building itself has failed to attract the exhibitions and events it was intended for and it can't easily be adapted for other uses due to its design. Patronage has been poor. Although other developments are underway in West Bromwich, it wasn't what [the area] needed." Sad to say, Will Alsop's pink-trimmed building has become a bit of a poster boy for the demise of the Bilbao Effect.

Stephen Snoddy, of Walsall's New Art Gallery, which itself launched in Bilbao-esque spirit in 1999, believes that arts regeneration works best as part of a place-making strategy, increasing visibility and interest.

"For example, the MK Gallery gave Milton Keynes a cultural identity that it never had before," he says. "I heard from the local authority that the Gilbert and George exhibition – the gallery's first exhibition in 1999 – did more for Milton Keynes than 25 years of ordinary marketing budget."

The BALTIC in Gateshead, where Snoddy also used to work, is also cited as an example of a gallery that has secured inward investment and raised land values. "It definitely affected property prices in Gateshead." Snoddy adds that the developer Urban Splash is now developing a site in Walsall, close to the gallery, complementing what Snoddy calls its 'new phase'. "It can work." he says. "After all, who was talking about Margate before?"