South African firebrand opposition politician Julius Malema says he has been denied a visa to attend a conference in the UK on 10 May.

Malema said the UK had no "substantial justification" for its decision, and he saw it as an "attempt to silence a dissenting political perspective".

In a leaked letter to Malema's deputy, the UK High Commissioner to South Africa, Antony Phillipson, said the Home Office had been unable to process his visa application in time for his trip.

Malema, the leader of the Economic Freedom Fighters (EFF) party, is a fierce critic of what he sees as "Western imperialism", and also advocates the nationalisation of white-owned land in South Africa.

A Home Office spokesperson told the BBC that they do not comment on individual cases.

In a post on X, the EFF said the High Commission had "actively delayed the processing and approval" of their leader's visa so that he could not speak at the University of Cambridge on 10 May.

He had been invited by the university's African Society to address its Africa Together Conference, the EFF added.

In his letter, which the BBC has been told is genuine, Mr Phillipson said that he wanted to "personally apologise" that the Home Office in the UK had been "unable to process the application in time owing to the necessary steps required to consider visa applications and the unfortunate timing of some recent UK Bank Holidays".

He added that he had taken a "personal interest in the issue" over the last week.

"I recognise that this will be deeply disappointing, especially as the delegation applied in advance and some paid for priority service," Mr Phillipson said, in the letter to the EFF's Godrich Gardee.

Mr Phillipson added that the Home Office had agreed to refund the application fee.

Malema said on X that the EFF delegation had been promised that "everything would be sorted", but received a "regret letter just hours before our departure".

"This is unacceptable and spineless," he added.

The UK had a bank, or public, holiday on 5 May.