According to a new study by youth charity Ditch the Label, there were 50.1 million discussions either about or with examples of racist hate speech between 2009 and mid-2021, from 263 million conversations analysed across both countries.
The report found that such conversations spiked around the time of major world events, which included the World Health Organisation (WHO) declaring the outbreak of COVID-19 to be a pandemic in March 2020, while the June 2020 Black Lives Matter protests and the murder of Sarah Everard (March 2021) also saw spikes.
Ditch the Label teamed up with Brandwatch for the report, with the latter provided the states.
Speaking to BBC Radio 1 Newsbeat, the charity's CEO Liam Hackett said: "We already know from research that people who bully and troll genuinely may have low mental health, they may have trauma, they may be in an abusive household, they may be being targeted and bullied themselves."
He pointed the organisation receiving an increase of "more and more extreme" incidents of hate speech and online abuse during this time period, with people stuck inside during the pandemic.
He added: "Then you throw in the mix that people have high disposable time, they're bored.
"They feel like they don't have control over their lives, it becomes a bit of a perfect storm."