The boyfriend of a corrupt Uzbek pop singer, socialite and former UN ambassador bought luxury properties in London worth more than £17 million using shell companies, The Telegraph can disclose, raising fears about money laundering.

Rustam Madumarov, who was in a long-standing relationship with Gulnara Karimova - the daughter of the former Uzbek dictator Islam Karimov - purchased four homes in Mayfair and Belgravia using a network of offshore accounts.

The properties - one of which was later sold for a £1 million profit - were acquired by two companies registered in the British Virgin Islands (BVI).

Questions have been raised about the possible source of the funds used to purchase the properties, which are thought to be owned for the benefit of the woman US diplomats once dubbed the “single most hated person in Uzbekistan”.

In a memo dated 13 September, 2005, US Ambassador Jon R Purnell accused Karimova of using her government connections to “usurp” and “crush” business competitors to satisfy her greed, and concluded: “The general public view her as something of a robber baron”.

Both Madumarov, who was sentenced to six years behind bars in 2014, and his girlfriend have been described as members of an "organised crime network" by prosecutors in their home country.