It’s a unique sort of history series, as much about the research as the characters

How do the shows come together?

We have two genealogists on the team [Sara Khan and Laura Berry], who begin to build a family tree in the very standard way, with births, marriages and death records. Then our historical researchers build up stories of individuals on that tree. We generally find interesting material but sometimes there’s not enough for a television story, in that we’ll have an amazing beginning, a middle, but no end because the records don’t exist. So we have to try to go in all sorts of directions and it takes months – on average around three months, sometimes much longer – before we even know if there’s enough material for us to make a film.

How does this research play into the final documentaries?

It’s a unique sort of history series, Who Do You Think You Are?, because it’s as much about the research as the characters. The research in many ways is the story, so a lot of the anecdotes that the researchers tell as they go along the way, from exciting discoveries they’ve made, actually help us decide what’s going to be exciting in the film. Everybody who works on the series has to be the kind of person who loves historical detail and nitty-gritty, frontline history research.

More archives are digitised now than when the programme launched in 2004. Does that make things easier?

I’m sure that is true, but we never seem to be able to do without the on-the-ground, in-person research either. The digitisation of records helps us know what’s out there, and maybe gets us to a point where we know something’s promising more quickly. But because when we ultimately film we need to see locations and archives and speak to archivists, there are no shortcuts for that.