The shadow home secretary Diane Abbott has pulled out of an interview with BBC Radio 4's Woman's Hour shortly before she was meant to take to the airwaves.
The radio show issued a tweet saying that the Labour team replaced her with Emily Thornberry, shadow foreign secretary, after Abbott was "taken ill".
It comes just hours after she appeared on Sky News and struggled to answer questions on security in London in the wake of the terror attack that killed seven people on Saturday (3 June).
She was asked about the recommendations made by the 2016 Lord Harris inquiry which looked at how to improve the city's preparedness for terror attacks.
Of the 127 recommendations, she struggled to name any of them despite saying she had read the full report.
The Labour candidate for Hackney North and Stoke Newington was trending on Twitter after she failed to speak up in the immediate aftermath of the London attack.
When she was asked about the points Lord Harris had made, Ms Abbott said it was "an important review and we should act on it".
It is unknown how long she will be unavailable for due to illness, with under 48 hours before polls open for the general election. In February, Abbott missed a key parliamentary vote on Brexit - to trigger Article 50 - citing illness as the reason.
International Development Secretary Priti Patel responded for the Conservatives by saying: "Jeremy Corbyn wants to make Diane Abbott Home Secretary in just two days but is hiding her away from voters.
"The woman who would be in charge of our police and the intelligence services cannot even be trusted by Jeremy Corbyn and John McDonnell to go on the airwaves to explain their shocking record on national security.
"Labour might be hiding her today but make no mistake – she will be in charge of our security and borders on Friday unless people vote for Theresa May and her Conservative team."
Her latest interview gaffe with Sky News comes a month after she was criticised for two interviews over Labour's police plans and the party's results in local elections, where on both occasions she struggled to remember the numbers.