The announcement came after speculations over the Jubilee weekend that the threshold of 15% MPs was reached.
Bradley said the confidence vote will be held this evening between 6 pm and 8 pm and the result will be announced shortly after.
If Johnson loses the vote, he will have to resign as the prime minister and a leadership contest will start immediately after.
Johnson has been harshly criticized for months over the lockdown parties at Downing Street.
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