Just throwing this in here, but a lot of companies do not allow holiday accrual whilst on sick leave.
I think you perhaps mean taking holidays not holiday accrual.
I suspect that is partly what is causing some of the confusion in this thread - that an employee
can request holidays (i.e. paid time off) during sick leave.
Requesting holidays doesn't mean you're necessarily going on holiday (you could simply decide to use those paid vacation days*) and likewise going overseas for a break can be done on sick pay (depending on circumstances), doesn't necessarily need to be taken as holiday.
*I took holiday to have knee surgery once, I didn't want additional paid time off as it would affect my profitability and therefore my variable pay
Ive just been signed off with anxiety and stress for 3 weeks. During that time i have a prebooked holiday to butlins. I will still be going - in fact the doctor encouraged me to.
Pre-booked being the important term here. My colleague had no holidays booked and didn't request them either AFAIK. His Phased Return includes a half day today and prebooked holidays tomorrow and Monday.
Nope, not at all. The important points here are the reasons he's off work and that the doctor has explicitly recommended going!
His reasons for being off work certainly don't prohibit him from going to Butlins and in fact, going to Butlins might well help with aiding recovery from the reasons he's off work. Whether it was pre-booked or not is completely irrelevant.