Leading article: Free speech's limits

The Home Secretary, Alan Johnson, is to ban Islam4UK on the grounds that its members have broken the law by glorifying terrorism. Proscribing private organisations through the powers of the state will always be a fine judgement. Ministers need to strike a balance between two public goods: public order and free expression. There will always be disagreement about where to draw the line. Time will tell whether Mr Johnson has got this decision right.

But either way ministers must avoid the trap of only treating the symptoms of extremism and neglecting its causes. Whatever the arguments about bans, the most effective way to combat the virus of hate-fuelled Islamism is through patient engagement with disaffected young Muslims.

In the end, the only way in which Islam4UK and its hateful fellow-travellers will be truly silenced is through the contradiction of their specious arguments and the exposure of their nihilistic agenda through open debate.