it all depends on what bit you fail, any circumstances you might have and the decision of the progress comittee.
for example i failed the first spot test but there is a second one in which you can make up any marks. hopefully i have

so as regards coursework there may be an opportunity to compensate in other bits.
the intergrated summative however is different. you need 50% on this to pass. if you fail you are enititled to a resit (long story, but i went and checked and you do have the right to a second attempt) if you fail the resit, then the decision as to what happens goes to a progress committee. here they look at how well you have done during the year, how well you did in the formative (so work hard for this) and any personal circumstances.
best case senario is that they let you resit the whole year, worst case, they kick you out.
there is another option depending on any personal circumstances you have, i had a lot of shit happen this year and was offered another option, but thats the worse that could happen, so you don't need to know that yet.
you have to be prepared that at some point you might fail something. the thing with most med students is that many have sailed through school getting straight A's, never failed anything, think med school will be a breeze and so when they do fail, all hell breaks loose.
having failed AS and A2 modules, struggled to get to med school and finally got in after an access course, i (and the others who came from clin sci bradford) are more prepared when things go a bit to pot.
if things do go wrong, best thing to do is don't go sit in a flump and sulk for weeks, get back up, get studying and pass the next exam/coursework.