Over a decade before Margaret Thatcher swept to power, another woman was running Britain from 10 Downing Street: Marcia Williams was the first ever female political adviser to a Prime Minister and was said to have a powerful grip on her boss.

A brilliant tactician, Marcia masterminded Labour Prime Minister Harold Wilsons multiple election victories. But misogyny, jealousy, a shocking private life and accusations of money-grubbing and bribery all contributed to her reputation as a public nuisance.

There is no doubt Marcia was outspoken, forthright and, by contemporary standards, deeply unconventional. But her critics failed to understand her unbreakable partnership with Wilson they were politically wedded to each other and equal contributors to his success.

In this fascinating biography, updated with new insight regarding Wilsons Downing Street affair with Janet Hewlett-Davies, Linda McDougall seeks to rescue Marcia from previously dismissive verdicts, suggesting a more nuanced perspective and restoring this trailblazing pioneer to her rightful place in British political history.