There had been widespread speculation that Mid Bedfordshire MP had been contemplating a move to UKIP.
However, it is understood the Ukip issue did not come up at her meeting with Sir George this afternoon, which was described as "convivial".
Ms Dorries said: "I am delighted. It is long overdue."
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Essex MP John Baron and South Northamptonshire's Andrea Leadsom could both put their names forward to be the next leader of the Tory party.
A devolution deal for Norfolk and Suffolk could be in doubt after two councils rejected the proposals.
It will be a fine and bright start to the day but it will turn cloudy from the west with outbreaks of rain arriving during the afternoon.