Reasonable request when tired?

Hi guys, need some help & advice.
Company i work for are currently planning to do a disciplinary hearing on me based on me refusing to take a unit from yard to service depot on the other side of town, in rush hour, after several 11+ hour shifts and me telling the transport manager i was tired and was not going to drive any more that day. I had informed his next in command approx 11 1/2 hours earlier that i would not be taking the unit over as i felt then that i would be tired based on previous days run being similar and my condition that day.

Am i right in assuming that, as long as i have made the manager aware that i am tired, i do not have to drive again until i am rested and feel fit and safe to drive?
Or can the Transport Manager tell me to drive even though i have informed him i am tired?

Any legislation stating either way as a fact he cannot wiggle out of would be much appreciated.

Thanks

if youve time on your card then they can tell you to do what they want.why shouldnt they?..best go for a limper job,or get a start at tescos…your obviously about as much help to them as a leaky space suit…mabey there wanting to sicken you so you leave. hello boss,il be too tired in a cpl of hours to bounce a unit across town??..you might not have wanted to,or couldnt be bothered,but isnt that part of the job?

Nothing like telling it like it is diesel…but i have to agree if you have time on your card left to do a " reasonable request " then I’m sorry but you have no defence against the disciplinary.

I know thats not what you wanted to hear.

Spot on. Boo hoo I’m tired. So many fannies in society.