Groups of artists and academics have written separate letters to The Telegraph and The Guardian urging the London Philharmonic Orchestra (LPO) to reinstate the four musicians it suspended after they signed a letter calling for the BBC to cancel an Israel Philharmonic concert.

Figures including film directors Ken Loach and Mike Leigh, composer Steve Martland and choreographer Siobhan Davies signed The Telegraph letter, in which they said they were 'dismayed at the precedent set by this harsh punishment'. The letter added: 'There is a clear link being forcibly created here between personal conscience and employment, which we must all resist.'

The Guardian letter, whose signatories included academics from the universities of London, Cambridge, Oxford, Edinburgh and Paris, said that 'the LPO's actions raises serious issues of freedom of speech', and concluded, 'Whatever our respective views on cultural boycotts, citizens of a democracy should be free to identify themselves with a cause without fear of discipline or silencing.'

The LPO's chief executive, Timothy Walker, told The Telegraph that if the four musicians had signed their names without affiliation there would not have been an issue. He said that players in the self-governing orchestra 'found it abhorrent that one group of musicians would try to stop another group of musicians playing a concert'.

The Telegraph also quoted Walker as saying: 'This all became an issue when we started to receive emails and letters from supporters, a lot of whom are Jewish and felt that the players were taking an anti-Jewish position. Some said they weren't going to come to the concerts or give us any money. Whatever the players' viewers are, we don't mind so long as it doesn't affect the company. I don't agree with music being used as a political football.'