I don't think it's classed as overtime. For each call thats attended a set fee is given
So if its 10 mins down the road and take 10 mins to complete they get the same fee as if it's 90 mins away and takes 3 hours.
To be fair it's a generous fee especially at weekends but thats to take account of the interruption to family life etc and the fact that he has to work a normal week at the same time.
As l understand it the emergency call outs are not compulsory. They can turn them down.
That may be the crux of it- it sounds like it may be treated as 'overtime' from a WTR point of view, and the company are a little peeved that he's taking the well-paid call-outs at the detriment of contracted hours (I know I would be if I was in their shoes- not that I would be, as I look after those I'm responsible for!)- it's a little while since I last had a read of the WTR (I've had decent employers for the past few years, so not needed to wield it!). Here's a link to the full regs:
http://www.legislation.gov.uk/uksi/1998/1833/contents/made
I'm pretty sure there's something somewhere in there about if 11-hour breaks are infringed, the employer should take reasonable steps to ensure the safety/wellbeing of the employee, but quite how this would slot into the situation as described, or the legality/morality of them saying he now owes them the missed hours, I'm not sure. Really someone at the employer end should probably be looking at when he's due to work next, and not giving him the option of doing the call-out if, for example, it means he's only going to get a few hours sleep before the next shift starts. Either that or they should say something along the lines of 'Bob, we really need you to do this call out- if you're able to take it, come in at midday instead of 8am, you'll still be paid a full day'.
