The team GB athlete, and her partner and Portuguese sprinter, Ricardo Dos Santos were handcuffed and searched in Maida Vale on July 4, 2020.
Ex-constables Jonathan Clapham and Sam Franks were dismissed without notice after a disciplinary panel found their actions amounted to gross misconduct.
The hearing found that the two former officers had lied when they said they smelt cannabis in Ms Williams and Mr Dos Santos' car.
Commenting on the incident, Sir Mark said: “Four officers said they smelt cannabis, the panel I think have believed two and disbelieved two others which - I don't yet understand the reasons for that.
“If officers have been dishonest, they clearly shouldn't be in the force.”
Going further, Sir Mark said he remained steadfast in his pursuit to improve standards in the Met, and said that the number of officers sacked for misconduct has increased by 70 per cent, with about 100 losing their jobs in the past year and that number likely to increase.
He told Sir Trevor Phillips on Sky News: “I'm operating in a paradox. The things I need to do, which is to take on these people who shouldn't be in the organisation, every one of those cases challenges trust, but we're going to do it.
“Meanwhile I've got tens of thousands of people doing amazing things to protect London.”
The page states that the donations have been a “huge comfort” for the officers and thanks those who donated as they have “genuinely made a difference”.