Early in the new film Denial, the Holocaust revisionist David Irving is seen challenging the historian Deborah Lipstadt at a lecture in Atlanta, Georgia.

The venue may seem familiar to some – it was shot in the Howard Hall at London’s JW3.

Raymond Simonson, JW3’s chief executive, said the filming had to be done “completely hush hush. Only two of us on the staff knew what was going on.

“The extras were bussed in. When some of our regulars wanted to know why people were coming with old-fashioned Walkmans, we said it was just a drama school using the place.”

Timothy Spall (above), who plays Irving, and Professor Lipstadt are to attend a premiere of the film at JW3 today.

The film credits include two New North London Synagogue members Natalie Grazin and Sam Cohen, who taught actors Rachel Weisz (who plays Professor Lipstadt) and Mark Gatiss (Holocaust expert Robert Jan van Pelt) to sing the memorial prayer El Mole Rachamim.