Police will formally interview three women allegedly held as slaves for the first time today.
The trio have had indirect contact with officers but police have had to wait until trauma experts gave them the go-ahead to take their accounts in person.
Commander Steve Rodhouse said: "We have not yet been able to formally interview the victims in this case so we don't fully understand the nature of the allegations. We are moving to a point where we will be able to interview the victims and our plan is actually to do so today.
"The victims are in the care of specialists who have got great experience of dealing with people who have been subject to trauma.
"We're working to that advice of those experts as to how best to handle those victims, to support them and of course to draw out the evidence we would need to substantiate any prosecution."
Documentary footage of the man said to have kept three women as slaves in south London has been uncovered by ITV News.
The political past of a couple accused of holding three women against their will for more than 30 years, has emerged.
A couple were arrested after police arrested three alleged slavery victims said to have been held against their will for at least 30 years.