Britain’s leading pro-Palestine group’s Twitter account has been hacked, with a message posted welcoming new Hamas terror leader Yahya Sinwar.

The Palestine Solidarity Campaign said it is looking into the breach, which saw a message tweeted stating: “Together we will build a more supportive UK.”

PSC’s official account posted the message on Wednesday at 12.30pm, which remained online for less than 10 minutes before being discovered and deleted.

PSC told Jewish News: “Our Twitter account was hacked and we are dealing with the security breach. That is not a tweet from us. The PSC has a longstanding policy of not aligning with any particular party or political faction. This tweet did not come from the PSC but from an unknown third party who gained unlawful access to our server. We are investigating the source.”

Sinwar’s appointment places one of the Islamic terror group’s most hardline figures in charge of operations in the Gaza Strip.

A senior commander, he was freed by Israel in a 2011 prisoner swap, after serving 23-year in prison. He was handed four life sentences in the late 1980s for tracking and killing ‘collaborators’ with Israel, according to Al Jazeera.

Sinwar replaced Ismail Haniyeh, who served as the prime minister of Hamas’s government following the 2007 takeover of Gaza.

The Palestine Solidarity Campaign's tweet