Andrea Leadsom is expected to pull out of the two-way contest to become the next Conservative Party leader and UK prime minister, the BBC understands.
A source close to the energy minister said "the abuse has been too great".
Mrs Leadsom was up against Home Secretary Theresa May in the race to succeed David Cameron as prime minister.
She apologised to Mrs May on Monday after suggesting being a mother made her a better candidate for the job.
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