In 1460 Thomas Cooke was elected MP City of London.

In 1462 Thomas Cooke was elected Lord Mayor of London.

In 1467 Thomas Cooke commissioned the building of Gidea Hall [Map]. It was completed by his descendant Anthony Cooke.

In 1467 Thomas Cooke was charged with high treason for lending money to Margaret (age 36), the queen of the deposed Lancastrian King Henry VI (age 45), on the strength of a confession of a statement obtained under torture from one Hawkins. Chief Justice Markham directed the jury to find it only misprision of treason, whereby Cooke's lands and life were saved, though he was heavily fined and long imprisoned. While awaiting his trial in the Tower his effects, both at his town house and at Gidea Hall [Map], were seized by Lord Rivers (age 62), then treasurer of England, and his wife was committed to the custody of the mayor. On his acquittal he was sent to the Bread Street compter [Map], and afterwards to the king's bench [Map], and was kept there until he paid eight thousand pounds to the king (age 24) and eight hundred pounds to the queen (age 30). Lord Rivers (age 62) and his wife (age 52), the Duchess of Bedford, also obtained the dismissal of Markham from his office for having determined that Cooke was not guilty of treason.

In 1470 Thomas Cooke was elected MP City of London.