Yevgeniya Vasilyeva, 33, on the right, is the alleged lover of Anatoly Serdyukov, 50, who was sacked last week by President Vladimir Putin after state investigators uncovered a £60m corruption scheme in Oboronservis, a defence agency where he was chairman of the board until last year.

Neither Mr Serdyukov or Miss Vasilyeva, a director of Oboronservis, have been charged but she is a suspect in the case and analysts in Moscow believe the former defence minister could soon be called in for questioning.

When police raided Miss Vasilyeva's luxury flat in the capital at 6am one morning last month they discovered Mr Serdyukov at her home, according to Life News, a well-resourced muckraking website with ties to the Kremlin and law enforcement agencies. State investigators reportedly seized £620,000 worth of diamonds, pearls and other jewellery, several antiques and a large sum of money during the raid.

It is not known who took the photograph, but it shows Miss Vasilyeva, a striking blonde, wearing a sparkly dress and leaning close to a chestnut-haired friend at what appears to be a New Year dinner in a restaurant decorated with tinsel. The friend is Yekaterina Smetanova, a real estate agent who was charged with fraud on Wednesday in the Oboronservis affair, along with her husband, Maxim Zakutaylo.

Investigators allege that employees of Oboronservis – an agency set up to sell off unneeded property for the defence ministry – invested heavily in military assets including a design institute that once developed rocket silos and then sold them at far below market value to commercial associates in exchange for kickbacks.

It is thought the information about Miss Vasilyeva's alleged affair with her boss may have been leaked because the father of Mr Serdyukov's estranged wife is Viktor Zubkov, 71, the powerful chairman of Gazprom who is a close ally of Mr Putin. Mr Zubkov is said to be angry with Mr Serdyukov's treatment of his daughter Yulia, 42.

Another theory suggests the minister was targeted because of his unpopular attempts at root and branch reform in the armed forces, which Mr Putin said in February would spend 23 trillion roubles (£485bn) on new weaponry over the next decade.

That theory strengthened on Friday when the president sacked the country's top general, Nikolai Makarkov, who had joined Mr Serdyukov in criticising Russian arms manufacturers for overcharging the state.

Miss Vasilyeva is currently being treated in hospital but will be questioned soon.