A controversial fertility doctor yesterday said he felt "overwhelmed" after dozens of families gathered to back him following an official investigation and allegations in a BBC documentary over his practice.

Parents and children gathered outside Mohamed Taranissi's clinic in central London to say they would not have had a family without his help.

One father said he believed the doctor had the "magic touch" after he and his wife had two children after paying thousands of pounds for treatment by the doctor.

On Monday, inspectors from the Human Fertilisation and Embryology Authority (HFEA) and police visited two London clinics run by the doctor.

The HFEA said it had been looking into Mr Taranissi's activities for some time.

Meanwhile, a Panorama documentary screened on the same day claimed that an undercover reporter was offered "unnecessary and unproven" treatment at Mr Taranissi's Assisted Reproduction and Gynaecology Centre (ARGC).

yesterday a group of around 100 people, made up of about 30 families, went to the ARGC to show their support.

They brought balloons, bunting, and banners criticising the HFEA and Panorama and backing the doctor's treatments.

When he arrived at the clinic they cheered with delight and chanted his name.

Mr Taranissi said: "I am just really, really overwhelmed. I think we do what we can do for people.

"That's how we work and that's how we would like to continue to work.

"Hopefully we can show people that what we are doing is right and will benefit a lot of people.

"When you see things like that you know you must be doing something right.

"People trust you and they come because they believe you are going to give them the best chance."

Asked if he was worried about what might happen in the future, he said: "I am not really concerned. I am very clear, I know everything will turn out for the best and maybe this was an opportunity for things to be resolved once and for all."

Mr Taranissi, 52, originally from Egypt, said his clinics treat up to 1,700 women a year and have had the highest success rates in the country since 1995.

Asked if he believed his critics were motivated by jealousy, he said: "This may be one of the reasons. It is human nature.

"Maybe if I was in the position of other people, I might have felt jealous as well, but I don't think much about this."

Outside the clinic, Cheryl Hudson, 38, an Oxford University academic who with husband Alan, 55, paid around £8,000 for successful fertility treatment and now has a two-year-old son Frank, explained why the families had gathered for yesterday's protest.

She said: "We wanted to really show the support of all the parents that Mr Taranissi has helped because he had an unfair trial on Panorama and they just showed one side of the story.

"We want to show the other side of the story, the wonderful success rate and all the families he's created.

"It is a celebration of our families that we wouldn't have had without him and a protest at the way he has been treated in the programme and by the HFEA."

She said she had had fertility treatment before but had become "sick of hearing" other doctors tell her to "go away and try again" for three years.

"Mr Taranissi was willing to do tests and find out what was the problem and what the treatment might be," she said.

She believed others criticised him because he was willing to "take risks and push the boundaries" and said parents were angry that they had been portrayed as "manipulated and exploited victims" when they were, in fact, well informed.

Another woman who had successful treatment, Catherine Garrett, 34, a solicitor from Harrow, north west London, also spoke out in support.

She and husband Mark, 37, a Rolls-Royce executive, spent more than £20,000 on treatment after she was told she could never have children because of a problem with the lining of her uterus.

They now have a five-month-old son, Freddie, and Mrs Garrett said of the doctor: "I think he is a wonderful man."

Nick O'Brien, 39, from Amersham, Bucks, and wife Natalie, also 39, had a son, Joe, after trying for four years.

They also had a daughter, Bobbi, which they also attribute to the treatment at the clinic.

Mr O'Brien said he had always been made aware of the "pioneering" nature of the treatment being offered and was "angry" about the way Panorama had portrayed Mr Taranissi.

He said: "Joe is the perfect example of a little boy. He is everything we have ever wanted.

"He is as fit and healthy as any other child. I firmly believe that Mr Taranissi has the magic touch."