In a humiliating blow, 21 Labour rebels, including Colin Challen MP (Morley and Rothwell) and John Grogan (Selby), voted with opposition MPs to defeat plans to outlaw abusive and insulting behaviour inciting religious hatred.
Mr Blair had been told by his Chief Whip Hilary Armstrong, who is in charge of party discipline, that he did not need to vote on the key measure. But the Government was defeated by the narrowest of margins of 283 to 282 votes – which it would have won had Mr Blair stayed to vote as the Speaker would have had the final say in a tie and voted with the Government.
Fiasco
Last night's fiasco, which also saw the Government lose on another technical measure, calls into question Ms Armstrong's future ahead of a Cabinet reshuffle.
She also miscalculated the size of the rebellion over the 90-days-without-charge element of last year's planned terrorism laws. Though the Racial and Religious Hatred Bill will become law, it has been considerably watered down.
The amendments, which were put down by the House of Lords, will restrict the new offence to inciting religious hatred to "threatening" words and behaviour rather than a wider definition wanted by the Government to include "insults" and "abuse".
The offence must also specifically be intentional and criticism and ridicule of religion would not be an offence.
Dominic Grieve, the shadow attorney general, said: " The Lords' amendments are infinitely better than the Government's proposals."
Home Secretary Charles Clarke accused opposition MPs of being more interested in damaging the Government than defending free speech.
anne.alexander@ypn.co.uk
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