British model Chloe Ayling's kidnapper sent a email threatening to auction her as a sex slave to the Russian mafia unless a ransom was paid for her safe return, MailOnline can reveal.

Chloe's former agent Phil Green revealed 'Black Death' kidnapper Lukasz Herba said he had five days to pay the money or the 20-year-old beauty would be sold the highest bidder.

The model boss claims Herba posed as Italian photographer called Andre Lazio and paid €1,000 up front to lure Chloe to a fake photo shoot at his bogus Bessis Mafique Studio in Milan.

Speaking to MailOnline, Mr Green said: 'Chloe had gone to Milan for the photoshoot on the Tuesday.

'The man checked out and it all seemed fine, I didn't suspect anything was wrong. 

'But then I didn't hear from her on Tuesday and by Wednesday morning I hadn't heard from her. 'Then at 10am on Wednesday morning this email landed in my inbox. It read, 'We've got Chloe Ayling. We are Black Death group. It is of supreme interest that you raise money. You should contact [three names] or she will be sold at auction on Sunday and handed to the Russian mafia. It went on: 'We require you to come up with an offer by Sunday or she will be placed for auction.'

Mr Green, a former lawyer who runs Supermodel Agency, said he was 'absolutely terrified'.

'I didn't know what to think. I spent five days thinking she was dead. Talk about sleep deprivation. I hardly slept for a week. It was a difficult time.'

He added: 'It has not got any easier since she has got back. We didn't expect for this to go global and get press from around the world.

He said Herba contacted his agency in March and booked Chloe for a motorbike themed shoot in Paris on April 22.

Herba specifically asked for Miss Ayling and paid up front for her trip to Paris where where she was met at the airport by chauffeur-driven car and stayed in a hotel off the Champs-Elysees. 

But that night the French capital was hit by a terror attack and a police officer was killed and two more were wounded close to her hotel. 

Mr Green said: 'The next morning Herba phoned to say that his studio had been ransacked in the chaos of the terror attack and his motorbike had been stolen. He said the shoot was cancelled.