Can F1 doctors use section 5 (2) to stop a patient leaving the hospital?

Currently doing my psychiatry module, and in the middle of SJT practice...

I came across an SJT question where an agitated overdose patient was trying to leave the hospital. The answer suggested (amongst other things) to get senior help, as junior doctors are not qualified to section a patient.

Are F1's allowed to use section 5(2) - doctor's holding power - to stop a patient from leaving the hospital in order to prevent them from causing further harm to themselves?

Would be useful to know before I'm stuck on a ward on my own at 3am with a suicidal patient running out the hospital!!

Thanks.

Authored By Dr Emily Lowe on Monday 12th November 2012