How many emails are they snooping on?

I see from a www.theyworkforyou.com alert that the Labour MP, Micheal Meacher (Oldham West & Royton) posted a written question in the House of Commons on 26 Nov 08...

To ask the Secretary of State for the Home Department how many e-mails and other electronic communications data were sent in the UK in each of the last three years; how many were monitored by the authorities in each year; and how many were found to be relevant to (a) terrorist activity and (b) crime in each year.

He'll be fobbed off of course, but I'd love to see the answer if he wasn't!