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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There'll be a few showers about on Saturday but it will slowly brighten up and Sunday should be mostly dry. It will stay cool in the wind.