Watch Simon Case's evidencepublished at 09:55 British Summer Time 23 May
Simon Case was due speak to the inquiry last year about his role running the civil service during the pandemic, but had to withdraw in October over health issues.
Although he has not yet given evidence in person, Case has already come up in the inquiry through published WhatsApp messages.
In messages from September 2020, the inquiry heard he told colleagues former prime minister Boris Johnson "cannot lead" and "changes strategic direction every day".
We won鈥檛 be covering today's inquiry appearance with regular text updates but if you鈥檇 like to hear what he has to say, click the play button at the top of this page.