When Sergi Prieto founded the world's first sex doll brothel in Barcelona, he claimed it was there to service 'all fantasies.'

But he insists there are some requests he turns down, with two of the most common being rape fantasies and those looking to have sex with dolls resembling children.

While he admits there are 'lots' of suppliers who will make dolls shaped like children, that is not a line he is willing to cross.

Sergi Prieto, the owner of the world's first sex doll brothel in Barcelona, says he regularly has to turn down requests from people looking to carry out rape fantasies or have sex with dolls that look like children (pictured, one of the dolls inside the brothel)

Speaking to the Daily Star, he said: 'That's an ethical option for us not to provide this kind of service.

'We could do that, but we don't want to promote this kind of behavior.'

'Some customers prefer the service because they have a rape fantasy,' he added. Obviously we don't want to promote this kind of activity.'

While Sergi says he often denies requests from these sorts of customers, business is still booming and he hopes to take his brothels worldwide.

Lumidolls offers punters half-hour sessions with one of their dolls for as little as £67 or £83 for a full hour.

The dolls, which are made from thermoplastic elastomer, come with their own personality and attributes and can be dressed up however the customer desires.

Prieto says there are 'lots' of suppliers who make dolls that look like children, but he made an 'ethical decision' not to provide the service to his clients (pictured, two of the brothel's dolls)

One of the most popular requests is for a schoolgirl uniform, Sergi said.

After the customer is finished the doll is thoroughly cleaned and disinfected, before being prepared for the next customer.

Lumidolls owns four of the robots, which cost a little more than £4,000 each.

Initially the brothel opened on Barcelona's famous Las Ramblas, but was forced to close after protests from local sex workers.

It has now moved to secretive location in the city that is only given out to paying customers.

Lumidolls is also looking for franchise owners who would be willing to take their business model around Europe, including in the UK.