It must be galling. At home they are treated like royalty, shrines are set up to worship them and millions follow the minutiae of their daily their lives. But while the stars of Bollywood cinema are adored by the Indian diaspora the world over, the majority of non-Indians remain oblivious to their fame.

Which is why Bollywood is on a mission to expand its reach, with its biggest, most bankable stars - Indian cinema’s first family the Bachchans - leading the assault.

Since July, the head of the clan, 66-year old Amitabh Bachchan, aka Big B, his son Abhishek and delectable daughter in-law Aishwarya Rai have been touring the world in a Bollywood song and dance extravaganza called the Unforgettable World Tour.

Showcasing the cream of Indian performing talent, and marking Big B’s return to the stage after more than 20 years, the multimillion pound tour will eventually reach 28 cities in five continents including dates in Switzerland, Kuwait and South Africa.

If anything was going to raise international awareness of Bollywood’s unique brand of magic, this should have been it.

But as the first leg of the tour - taking in cities in the USA and Canada, Trinidad and Tobago, and this weekend London - draws to a close, hopes for world domination appear frustrated. For while the shows have been filled with committed fans from the Indian sub-continent, they have failed to draw in the Western crowds.

According to Shekhar Ravjiani, one half of the musical duo Vishal-Shekhar who are part of the show, to date 85-90 per cent of audiences have been from the diaspora, leave at most 15 per cent Western audiences.

Bollywood cinema is India’s foremost artistic export, so the narrowness of these audiences is striking. It’s hard to imagine a Bolshoi world tour playing to 90 per cent Russian émigrés or the Berlin Philharmonic appealing exclusively to German expats.

Part of the problem could be financial. Promoters have been charging as much as £250 for a ticket, and with credit crunch sliding towards recession on both sides of the Atlantic, it’s not surprising only the most die-hard fans are prepared to fork out.

Even the Bachchan's greatest admirers in Trinidad and Tobago were shocked at the prices they were being asked to pay. Local promoter Mahendra Persad complained that even with the inflated ticket price, the exorbitant cost of accommodating the Bachchans, with their vast retinue and extravagant props, had rendered the venture financially unviable.

In Toronto, it was dubbed the Unaffordable World Tour. And in Vancouver, the planned show was cancelled when it failed to sell out. A failure, the tour’s producer Wiz Viraf Sarkari, was yesterday blaming on the local promoter.

There are also still tickets available for Sunday’s London show. And while Viraf Sarkari was stating confidently that it would sell out, a spokesperson for the O2 Arena refused to reveal how many seats remained unsold but said the target was to reach 15,000 - 2,000 short of the venue’s 17,000 capacity.

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