The BBC Trust has defended the censoring of a rap song which contained the words "Free Palestine".

The Trust's ruling - which was made on the basis of upholding impartiality - prompted pro-Palestinian activists to claim that the Corporation had an "institutionalised bias against the Palestinians".

When rapper Mic Righteous performed on a BBC Radio 1Xtra show, he sang: "I still have the same beliefs/I can scream Free Palestine/Die for my pride/Still pray for peace."

But when the track was broadcast in December 2010, BBC staff covered the word "Palestine" with the sound of breaking glass - often used to silence foul or abusive language.

The corporation originally said its production team had edited the song to "move away from any potential claim of not maintaining due impartiality".

Breaking glass covered the word 'Palestine'

Last week, the BBC Trust said it was satisfied that the BBC's decision to reject a dozen complaints from pro-Palestinian campaigners had been correct.

But the Trust admitted the handling of the issue had been "over-cautious" and that the corporation was now "looking to learn from the way the matter had been handled". It is likely the song will be played in full in future, with "contextualisation".

Mic Righteous, 21, raps about the "geopolitical consequences of US foreign policy". His parents fled Iran for Kent in the 1970s. His brother is former world boxing champion, Takaloo.

The Palestine Solidarity Campaign's Amena Saleem said: "Putting aside the BBC's ignorance of international law, which states unambiguously that Palestine is under occupation, we have argued that this decision clearly shows the BBC's bias against Palestine.

"It's a great shame that, in the year of the Arab Spring when the BBC was covering the struggle of millions of people for freedom, it remained wedded to its institutionalised bias against the Palestinians and refused to even recognise the fact of their occupation."

Last May, MPs, academics, lawyers and artists - including Alexei Sayle, Miriam Margoyles, Benjamin Zephaniah, Ken Loach, Ilan Pappé and Jeremy Corbyn - wrote to the Guardian to condemn the BBC's reaction.