A woman suspected of being a ringleader of a criminal network involved in trafficking young women from Nigeria to Europe for sexual exploitation has been charged with modern slavery offences.

Josephine Iyamu, 50, a British national, was arrested after she landed at Heathrow on a flight from Lagos, Nigeria, on 24 August, the National Crime Agency (NCA) said.

Iyamu, from Bermondsey in London, was charged with arranging to facilitate travel of another person with a view to exploitation – an offence under the Modern Slavery Act – and was remanded in custody. She will appear at Birmingham crown court on 22 September.

Thirteen men have been arrested for suspected slavery and immigration offences after police raids in Hertfordshire and north London.

Immigration enforcement visited a business address on the Baldock industrial estate off London Road. Picture: Hertfordshire Constabulary

Six men who were identified as potential victims of trafficking or slavery and have been taken to a safe place.

Over 120 officers, immigration officials and fire fighters carried out the raids on five properties.

The police have described the victims as living in "appalling and unsafe conditions".

Raids were carried out at a business premises on an industrial estate in London Road and a residential address in Park Close, Baldock, and a residential address in Winterscroft Road, Hoddesdon in Hertfordshire..

In Barnet a house in Kenerne Drive and a commercial property in Wycherley Crescent were raided.

Those arrested for immigration offences to be dealt with by Immigration Enforcement. Those arrested on suspicion of trafficking or slavery offences are now in police custody.

The Red Cross gave support to the victims in a reception centre while the fire service condemned the living quarters at the business address in Baldock due to safety concerns.

Det Insp Luke Whinnett said: "This operation shows that partnership commitment as different agencies have come together, acting on intelligence that we have received.

"Slavery and trafficking does occur in Hertfordshire and I would encourage people to look out for the signs and report any concerns they have to police."