The TUC said firms should not put off the ‘inevitable’ ban, which is due to come into force in the summer of 2007.
Around 700 workers die every year through passive smoking, according to official research, proving the case for an immediate ban.
Smoking was banned in Scottish workplaces in March and a Welsh ban will come into force on 2 April.
"For every month that employers wait to introduce a ban, more employees will die or become seriously ill as a result of second-hand smoke," said Brendan Barber, TUC general secretary.
"There is no sensible reason why employers can't be sitting down with staff now to talk about how the ban will happen and how to make every workplace a safer, healthier place to be," he added.
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