As Secretary of State (1573-90), Walsingham was in charge of Elizabeth's secret service, controlling a network of spies and informers all over Europe - largely at his own expense.

This enabled him to discover several plots against Elizabeth, including those led by Roberto di Ridolfi (1571), Francis Throckmorton (1584) and Sir Anthony Babington (1586).

Like Burghley, he was completely loyal to Elizabeth. He was also a strong Protestant and utterly opposed to Mary Queen of Scots - 'that devilish woman', as he called her. He was convinced that she was the cause of all Elizabeth's troubles and that as long as she lived both Queen and country were in the greatest danger.