A violinist who was suspended by the London Philharmonic Orchestra after signing an anti-Israel letter is to take the orchestra to an employment tribunal.

Sarah Streatfeild was among two dozen musicians who signed the letter, published in the Independent, encouraging the BBC to cancel the Israel Philharmonic Orchestra's Proms appearance at the Royal Albert Hall last September.

The LPO initially said the players' views were "a private matter" and that "music and politics do not mix", but later suspended Ms Streatfeild and three colleagues for nine months. The ban was later reduced to six months.

Ms Streatfeild is now thought to be demanding a public apology and compensation for loss of earnings and injury to her feelings. She is expected to argue that her humanist beliefs led her to sign the letter, and that she believed it was intended to be sent only to the BBC management and not made public.

Her lawyer, Shazia Khan, confirmed proceedings had been issued and said Ms Streatfeild "unequivocally rejected" any link to the Royal Albert Hall protests. Ms Khan told the Guardian that "making a stand about the invitation to the IPO was a question of conscience for my client". Ms Streatfeild was "devastated" that her career had been halted.