He was one of the Commissioners selected to treat with Charles in 1642, and after the failure to open negotiations he was anxious to retire from public affairs.

However, he was persuaded not to resign, and in 1644 was appointed one of the Committee of both Kingdoms.

He became a leader of the independent party, and did not always see eye to eye with Cromwell.
He quarrelled with his party, disapproving of its attitude towards Purge's Pride and the trial of the King.

After this he took little part in politics, though the Protector sought, and he gave on occasions, his advice.

In February, 1660, he was elected to the new Council of State at the head of the list, and in the Convention Parliament represented Nottingham.