The armed police looking on from their camouflaged surveillance posts in the woods were convinced the gardener's van which emerged from behind the gates of the secluded villa was their cornered target's final attempt to escape. As the van left, officers radioed colleagues some distance away and ordered a armed "hard stop" in an effort to stop him. Yet when the van was stopped by armed officers moments later, they discovered the van was empty and the gardeners were genuine. Undeterred, the police quickly capitalised on the mix-up. The gardeners were persuaded to change clothes with police and readily provided the access code for the formidable security gates. So it was that a humble workman's van, acting as an improvised Trojan horse, ferried a heavily armed French tactical firearms team past the security cameras and into the heart of the fugitive banker Mukhtar Ablyazov's secret bolthole in the south of France.

The officers who entered the main building quickly found the Kazakh businessman, accused of one of the world's biggest frauds, seated at his computer, unaware of his imminent arrest. Ablyazov, arrested on an Interpol warrant, is now facing extradition from France to Ukraine, where he is wanted for questioning about allegations of banking fraud.

The dramatic final moments of Ablyazov's arrest emerged yesterday in France as full details of the 18-month hunt for him after he fled Britain last year were revealed.

Download the new Independent Premium app Sharing the full story, not just the headlines

Ablyazov was hunted by British private detectives when he fled the country after the High Court sentenced him to prison for contempt of court. The banker has been accused of embezzling $6bn (£3.9bn) from Kazakhstan's BTA Bank. The bank fought to get the money returned through a series of civil court battles, opposed at every stage by the businessman, who claimed he was the victim of political persecution as a result of his opposition to Kazakhstan's autocratic President, Nursultan Nazarbayev.

The banker, whose country's elite has grown wealthy on the proceeds of vast oil and gas reserves, insists he is the target of a political conspiracy after he left his post as energy minister and became a prominent opponent of Mr Nazarbayev. Ablyazov funded a pro-reform party in 2001, earning himself a six-year prison term for abuse of public office. After he was pardoned by Mr Nazarbayev in 2003, he presided over rapid growth at BTA, allegedly plundering its assets until he fled to London 2009 and successfully applied for asylum in 2011. Kazakh prosecutors have described him as the head of an extremist, criminal conspiracy bent on "seizing power by inciting civil strife and hatred".

In May, Ablyazov's wife and six-year-old child were controversially detained and then taken from Rome to Kazakhstan, sparking a domestic political crisis in Italy. The Italian government says it was not properly informed about the expulsion and has asked the head of police to explain what occurred. Ablyazov's family says that the wife, Shalabayeva, and the couple's six-year-old daughter, Alua, are "in danger" in Kazakhstan.

The British private detectives tracked down the missing banker after following a Ukrainian lawyer, Olena Tyshchenko, from the High Court in London, where she sought an adjournment of legal proceedings to seize Ablyazov's assets. Ms Tyshchenko, who lives with her children in the luxurious private St George's Hill estate in Surrey, was then trailed to the south of France, where she was spotted meeting Ablyazov in a waterfront villa in Miramar.

According to legal sources, the British detectives were unaware of Ablyazov's presence until he was spotted in his boxer shorts placing flowers in a vase and rearranging the bed before closing the curtains. The properties were kept under observation, and the financier's personal staff later led investigators to another, more secluded property north of Cannes in the village of Mouans-Sartoux. The villa, where French police eventually arrested him last week, is close to where Ms Tyshchenko also owns property. While Ablyazov was kept under surveillance, Ms Tyshchenko was followed to Moscow, where she secured a divorce from her husband Sergei, a Ukrainian banker. Ms Tsychenko then returned to the south of France, where she socialised with Ablyazov.

Ablyazov, who appeared in court in Aix-en-Provence, is expected to apply for release from detention this week. In April, Ablyazov's former bodyguard, Aleksandr Pavlov, was detained in Madrid, Spain, accused of bank fraud and terrorism charges, which he denies.

Legal sources said the Ablyazov investigation had been led by the British corporate intelligence firm Diligence. When approached, a company spokeswoman said it had a policy of not confirming or denying its involvement with projects or the identity of clients.