George Limb was a politician. He was present at the signing of the Treaty of Versailles in 1919 and a conference in Munich in 1936. His career ended when he leaked an government document at the request of Winston Churchill. By 1940, he was directing much of the organised crime in London.
He met the Seventh Doctor and Ace when they were searching for a sphere which turned out to be a Cyberman time machine from the future. Limb was providing Cyber-technology to the British and the Nazis, hoping this would accelerate the advancement of human technology.
When a dormant Cyber-army was awakened and began killing people in the area, Limb tried to escape in the damaged time machine. The Doctor believed that both the machine and Limb were destroyed. (PROSE: Illegal Alien)
However, Limb survived and did more time travelling. He saw that he would eventually be turned into a Cyberman and tried to change history to avert this. All this accomplished was to create multiple timelines which were straining the Time Vortex so much it was in danger of collapsing. He had one of his employees, Jimmy, kill a version of Ace and leave her body for the Doctor to find, to lure him to Limb and get him to change his fate.
As invaders from one of the timelines attacked London, he tried to escape again in the time machine, which he had repaired with a new dimensional stabiliser. Before he could fully dematerialise, Jimmy crashed a car into the machine and died. Limb was severely injured and the machine irreparable. Realising his fate was sealed, he asked for the Doctor's help. The Doctor gave him Jimmy's gun, and Limb killed himself. (PROSE: Loving the Alien)