This is an issue on which there is little or no chance of convincing anyone who has already made a decision on the validity of the opposing argument. Only those who are undecided or unaware of the issues are likely to be won over.
I think that's a little pessimistic. No-one in their right minds could support this Bill. It's merely a question of getting them to let go of their affiliations and debate the pros (virtually none) & cons (immense).
I'd suggest remaining calm: tell him it's a complex issue and that you don't expect him to change his mind today, merely that he'll be open minded enough to see alternative views.
I presume GBFNJ knows what Salter's support is based on:
http://www.theyworkforyou.com/whall/?id ... 526#g303.2
He describes himself as a libertarian and dedicated to his constituents. Should be a piece of cake.
I'd start by countering his arguments, you can demolish the identity theft one with this document:
http://www.theregister.co.uk/2005/05/25 ... fraud_con/
Then ask him on what basis he would vote. Get him to emphasise that he'll vote for the benefit of his constituents. Then start to talk about the costs & the loss of freedom.
Has the Government yet released all documents relating to the Reading Trial?
There's a document here which has good counter-arguments:
http://www.no2id.net/downloads/print/NO ... N_text.pdf
Ask your friends if you can practice convincing them.