A high-profile IVF doctor been given a firm rebuke by the regulator.
Mr Taranissi is Britain's most successful test-tube baby doctor
Mohamed Taranissi, who runs a top London clinic, has been barred from being the "person responsible" for ensuring the clinic abides by the law.
But he will still be allowed to treat patients at the Assisted Reproduction and Gynaecology Centre (ARGC).
The Human Fertilisation and Embryology Authority made the decision after another clinic run by Mr Taranissi treated patients without a licence.
The "person responsible" is the official who is in charge of ensuring the clinic abides by the regulatory requirements under the law.
Mr Taranissi now has three weeks to nominate someone else.
The HFEA ruled that treatment took place at a second clinic run by Mr Taranissi - the Reproductive Genetics Institute - without a necessary licence.
The regulator said that clinic must now only be allowed to act as a storage facility, but again Mr Taranissi will not be able to be the "person responsible" under the law.
The HFEA said that Mr Taranissi had "failed to discharge" his duty as person responsible under the law and it had "ceased to be satisfied that the character of [Mr Taranissi] is such as is required for the supervision of the licensed activities".
In a statement, Mr Taranissi said: "We are pleased to have been told that we can continue to work and my priority now is my patients.
"The last few months have been extremely distressing for all our patients and staff."
But he added he would be appealing certain findings.
The latest ruling comes after raids carried out by the HFEA at the two clinics were ruled unlawful by the High Court.
The HFEA, accompanied by police, searched both clinics in January.
But a judge recently quashed both warrants and awarded Mr Taranissi his costs after the regulatory body admitted they were not "legally watertight".
The raids were carried out on the same day that a Panorama programme about Mr Taranissi was broadcast.
He is suing the BBC for libel saying that the allegations made in that programme were inaccurate.
The ARGC has consistently achieved the highest live birth rates in the UK every year since it opened in 1995.