The mobile phone operators are up to their tricks again. I've just come back from a trip to Germany, and the good news is that - thanks to Viviane Reding and the EU - I could call back to the UK for just 25p a minute on my UK SIM.

However, I also have a German SIM on a pre-pay tariff, which I bought to save me from having to pay to receive the mostly unsolicited calls I get while at events such as CeBIT.

That's still good value, not least because it charges me just 24c (about 17p) per MB for data, versus the £3/MB that my UK network charges - and even the latter is a bargain compared to the rip-off data roaming rates charged by some UK networks.

However, when it comes to international calls, my German SIM looks like less of bargain, as it charges a standard rate of €1.84 (£1.31) a minute.

That means that if, during CeBIT next year, I need to call a colleague who's in the next hall but is roaming with their UK phone, it will cost me more than five times as much to make the call with my German phone - with both of us in Germany! - than with my own UK phone.

It is one of the inevitable consequences of regulation that you will have forgotten something. There will be loopholes somewhere, and that the regulated will drive a bus through them if possible.

The two that have come to light so far are roaming tariffs for data, where BlackBerry addicts have been hit with bills for hundreds of pounds, and now the lunacy of roaming users getting cheaper international calls than home-network users. Has anyone spotted others yet?