PM's variable powers

• How effectively they provide naitonal leadership in times of crisis
• Size of majority e.g. May's minority government
• Personality, leadership style and popularity - May had a permanent low level of voter approval, 2007 - Tony Blair’s reputation deteriorated due to Iraq war; defeated four times in his last year, 2022 - Johnson resigned over Partygate
• Party unity - May was unable to unite her party around Brexit meaning her authority was fatally compromised