Thames Valley Police Chief Constable Sara Thornton has ruled herself out of the running to replace outgoing Sir Ian Blair as Britain’s most senior officer.

Ms Thornton, 45, was tipped by a Sunday newspaper to become the first female Metropolitan Police Commissioner.

Sir Ian will step down from the role at the end of this month after criticism over the shooting of Brazilian Jean Charles de Menezes and allegations of racism within the force by Deputy Assistant Commissioner Tarique Ghaffur.

But mother-of-two Ms Thornton this morning distanced herself from the role.

She said: “I do not plan to apply for the role of Commissioner of the Metropolitan Police Service. I have commitments here and now in the Thames Valley.”

Ms Thornton spent 15 years with The Met before being appointed Assistant Chief Constable of Thames Valley Police in 2000.

She was appointed Chief Constable in April 2007.