On Call Standby rates

[REByers]

Just found this forum and it looks like there is some good feedback in here, so here is my newbie question to start:

I am the Head of Operations at a software house and we are looking at introducing 24*7 IT engineering support for our products being run on customer sites 9around the world).

Our current engineers have normal office hours contracts (we are in the UK), and I am interested in what would be considered to be a reasonable standby rate (not call out rate, we are happy with this) compared to other organisations out there.

I did this type of thing with a company 10 years ago (remote dial in from home) and the standby rate then was £5 per hour.

Any experience out there?

Thanks, in advance, Rick