Video report by ITV News Correspondent John Ray
Boris Johnson shares Home Secretary Priti Patel's view that grime artist Wiley's anti-semitic social media posts were "abhorrent", Downing Street said.
Ms Patel said on Sunday that social media companies must act faster in removing “appalling hatred” from their platforms.
Police are investigating a series of comments made on the musician’s Instagram and Twitter accounts on Friday that led to him being banned from both for seven days.
The Prime Minister’s official spokesman said: “Social media companies need to go much further and faster in removing hateful content such as this.”
The Home Secretary has written to Twitter and Instagram seeking an explanation and the government expects a full response.
“The message is clear: Twitter needs to do better on this,” the spokesman said.
Mr Johnson is not joining a boycott of Twitter in response to the furore because of the need to communicate “important public health messages”.
“But at the same time we have set out very clearly that Twitter’s performance has not been good enough in response to the anti-Semitic comments made by Wiley and it needs to do much better,” the spokesman added.
Following Wiley’s posts, Twitter was accused of “ignoring anti-Semitism” as his tweets were still visible 12 hours after they were first posted.
A number of tweets have been removed and he has been given a seven-day ban by the site.
On Sunday, a spokesperson for Facebook, which owns Instagram, said the platform had also issued the rapper with a seven-day block on his account.
Twitter previously said Wiley’s - whose real name is Richard Cowie - account had been temporarily locked “for violating our hateful conduct policy”, while Facebook said there was “no place for hate speech on Instagram”.
Britain’s Chief Rabbi also accused Twitter and Facebook of lacking “responsible leadership” in their response to Wiley.
In letters sent to Twitter boss Jack Dorsey and Facebook chief executive Mark Zuckerberg, the Jewish leader said: "This cannot be allowed to stand. Your inaction amounts to complicity."