How many hours can work force me to do without a break?

[littlemissangrypants]

I'm a care worker on a 19 hour a week contract. This tends to involve 1 sleepover so effectively 29 hours.
At the moment I'm actually working 37 hours over three days. Work force me to work extra hours all the time. I'm likely to be told i have to work three shifts. Starting friday at 3pm and finishing sunday at 6pm. is this actually legal?

[fledtoscotland]

I think it depends on the wording of your contract (Flowery is the authority here) but I'm NHS staff and we have to have 11hrs between shifts.