Probably, they are most likely 22.2mm. If you're using road calipers, you should really use flat-bar road levers, as they have the correct pull ratio.
Thanks, hadn't realised that there were road flat bar components. Tiagra should do the trick http://www.ukbikestore.co.uk/product/129/shimano_bl4600/shimano-bl-4600-tiagra-brake-levers-for-flat-handlebars.html
@O'Shane started
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Thanks, hadn't realised that there were road flat bar components. Tiagra should do the trick http://www.ukbikestore.co.uk/product/129/shimano_bl4600/shimano-bl-4600-tiagra-brake-levers-for-flat-handlebars.html