There's a drum of the 1.00mm flat twin and earth stuff in my garage that tells me that it is for lighting curcuits but, unlike its 2.5mm neighbour, doesn't say what its rating is. The following link would have you believe that 1.5mm is limited to 18 amps in free air. My 2.5mm cable says it's limited to 24 amps in free air, and that agrees with the following link. This link is to a site more for DIY than industry but it might be a help.
http://www.diydata.com/materials/ele...tric_cable.htm