Later this week the government will unveil its new official definition of what constitutes extremism which is intended to crackdown on Islamist and far-right extremism.
Three former Tory home secretaries, Dame Priti Patel, Sir Sajid Javed and Amber Rudd, have signed a joint statement with others warning about the risks of failing to get cross-party political agreement on what constitutes extremism.
It is expected to be defined as the promotion of an ideology based on violence, hatred or intolerance.
But those writing today’s letter warned against political parties using the issue “to seek short term tactical advantage”.
We spoke to Fiyaz Mughal, who was due to become the government’s adviser on anti-Muslim hatred, but has said he stepped back after abuse and threats from the far-right and Islamists.