The Cinescapader: 2012

Directed by Ken Russell
Produced by Harry Saltzman
Written by Len Deighton (novel) and John McGrath
Starring Michael Caine, Karl Malden, Ed Begley, Oscar Homolka and Françoise Dorléac

Billion Dollar Brain is the third of the Harry Palmer film series, preceded by The Ipcress File (1965) and Funeral in Berlin (1966). It is the only film in which Ken Russell worked as a mainstream 'director-for-hire', and the last film to feature actress Françoise Dorléac.
A fourth film in the series, an adaptation of Horse Under Water, also to be released by United Artists, was tentatively planned but never made. However, Caine played Palmer in two later films, Bullet to Beijing and Midnight in Saint Petersburg.

Location filming for Billion Dollar Brain took place in Helsinki and other parts of Finland, including Turku. The Riga scenes were filmed in Porvoo, also in Finland.
Scenes involving "The Brain" were filmed in Honeywell facilities and featured a Honeywell 200 mini-computer. The remainder of the film was shot in the United Kingdom.
Scenes on the ice were filmed on a disused airfield which was covered with a layer of salt.
All other scenes were shot at Pinewood Studios, including the scene where Midwinter's convoy falls through the broken ice - this was done in a giant tank with slabs of polystyrene used to represent the ice itself.
The large size of the tank was deemed necessary because of the decision to use real vehicles instead of miniatures. -Wikipedia

Harry Palmer’s office, over the surgical appliance shop, is at 297 Pentonville Road, London, England, at the junction with Gray’s Inn Road opposite Kings Cross Station.