There were concerns the messages wouldn't survive after an unexpected downpour on Thursday evening.
Staff from the Manchester Art Gallery and archives team rushed to the mural as soon as the rain started and were relieved to see that despite being very wet, the vast majority of the messages survived the inclement weather.
Asked why the messages are so important, Larysa Bolton, Senior Archivist at Manchester Central Library said: "It's about Marcus and it's about his lived experience.
"It's the fact he has to deal with huge amounts of racism while he's just doing his job. And everybody's turned up to say they've got his back - it's just simply that that makes it so important."