Leonard Sachs, playing Svaars (uncredited) was left in the room with the revolver; his clothes had also been fireproofed and in the long-shot flames licked from the jelly which had been put on his back.

"[4]The Monthly Film Bulletin wrote: "The anarchist outrages are shown more or less as they happened, with scenes reconstructed from old newspaper photographs and a convincing-looking Winston Churchill (Jimmy Sangster) superintending the final battle as Home Secretary.

But instead of sticking to the facts, which were astonishing enough, the film is spiced with the pseudo-thrills of a novelettish romance – attempted rape, pastiche Russian music and a glut of melodramatic clichés.

To make matters worse, the characterisation is glib, important incidents are presented obscurely and banal dialogue over-emphatically delivered.

The Jimmy Sangster-Alexander Baron screenplay is sound and keeps tension to a high level, while offering the directors a splendid chance of bringing some dramatic vitality to the final siege.