Sir Francis Walsingham definitely thinks so, and will use any means to convince Elizabeth to eliminate Mary.

When this was found out, he begged Sir Francis Walsingham's intercession with his mother.

He was recalled in August 1570 and replaced by Sir Francis Walsingham.

His character was modeled after Elizabeth's real life spymaster Sir Francis Walsingham.

He was employed in political affairs by Sir Francis Walsingham, after whose death he retired into private life.

(This caused some difficulty with the College that had to be resolved by Sir Francis Walsingham).

It seems quite likely that he had in fact been an agent of Sir Francis Walsingham all along.

He was friend to Sir Francis Walsingham, head of the government's secret service.

After his death, she married Sir Francis Walsingham in 1566.

In 1583, he married Frances, teenage daughter of Sir Francis Walsingham.