The Fifth Citadel (audio story)

 was the second audio story in Big Finish Productions' second series of Counter-Measures.

Publisher's summary
People are falling ill near Holborn and displaying a sickness with all the hallmarks of radiation poisoning. While Gilmore and Allison look into a graveyard, Sir Toby and Rachel venture underground to meet an old friend with a desperate scheme.

Cast

 * Simon Williams - Group Captain Gilmore
 * Pamela Salem - Rachel Jensen
 * Karen Gledhill - Allison Williams
 * Hugh Ross - Sir Toby Kinsella
 * Celia Imrie - Dr Elizabeth Bradley
 * Philip Pope - Templeton
 * Mandi Symonds - Bridget

Continuity
to be added