A diamond ring worth more than a million pounds has been seized by British authorities investigating the unexplained wealth of a jailed Azerbaijani banker and his wife.Jahangir Hajiyev bought the spectacular 8.9 ct Cartier ring eight years ago in Harrods, but the item was seized by agents from the National Crime Agency while it was being repaired at a jewellers.The NCA believes the source of the funds to purchase the jewellery requires further investigation.The 57-year-old was chairman of the International Bank of Azerbaijan from 2001 until 2015, but was sentenced to 15 years imprisonment a year later for defrauding the bank out of £2.2 billion.Two Unexplained Wealth Orders were granted against the financier’s wife Zamira Hajiyeva concerning properties worth a total of £22 million under the first UWOs in the UK. The powers, which came into force at the beginning of 2018, allow investigators to look into the source of wealth of politically exposed persons.These are people from outside the European Economic Area in a position of power that makes them liable to bribery or corruption, or those with suspected links to serious or organised crime, who are unable explain the source of their wealth. Zamira Hajiyeva is under investigation into the source of her wealthCredit:Haqqin.az/east2west news Despite this, at the time of his arrest his wealth was estimated to be in the region of £55 million. UK authorities want to know how the couple could afford to buy their £15 million house in Knightsbridge as well as the Mill Ride golf and country club in Ascot, bought for £10.5 million. It was alleged that she paid a deposit of £4 million for the house in 2009 and had cleared her £7.4 million mortgage in just five years.Details of Mrs Hajiyeva’s lavish spending habits, which were laid bare in the court process, revealed that she had spent £16.3 million at Harrods between 2006 and 2016.NCA investigators claimed she had used 35 different credit cards issued by her husband’s bank to fund shopping sprees and on one occasion had spent £150,000 on jewellery.She is also said to have owned a £35 million private jet and had a wine cellar stocked with some of the world’s most expensive vintages.At Westminster Magistrates Court, District Judge Michael Snow granted detention of the ring, worth £1.19 million, for six months to allow further investigation in order to determine whether the item is recoverable. It was noted that when her husband worked for the state bank in Azerbaijan, his salary was estimated to have been around £54,000 a year. A sapphire and ruby serpent pendant – Boucheron (Guide price £80,000 – £120,000) was seizedCredit:National Crime Agency When Mrs Hajiyeva unsuccessfully attempted to overturn a UWO in October, her lawyers claimed her husband’s conviction was the result of a “show trial” and that his guilt “had been determined by the presidential administration in advance”.In November the NCA seized 49 items of jewellery with a value of more than £400k from Christie’s auction house in London where they were being valued for Mrs Hajiyeva’s daughter.Among the items were a Boucheron sapphire and ruby necklace valued at up to £120,000.Investigators also seized a Van Cleef & Arpels pearl necklace which was valued at £20,000 despite having originally been purchased her husband in San Moritz in 2008 for £280,000.The NCA said Christie’s auction house had co-operated with the investigation and had complied with a formal request for information regarding the listed assets.They added that they had seized the items because investigators believed that the source of the money that had been used to buy them warranted further examination.Mrs Hajiyeva, 55, is also facing extradition to Azerbaijan over allegations of embezzlement.She has denied that the source of her wealth is illegal. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.