No, if I went to the bookies today and put £999 on City at 1/1000, and you put £6.66 on the scum at 150/1, then the bookie would have £1005.66 and he would be guaranteed to have to pay out exactly £1000 to one of us when it's settled (again, ignoring other teams to simplify the maths). He would be guaranteed a profit of £5.66 whoever won it which is a profit margin of just 0.566%.
Worth noting that that profit margin is ridiculously small - it's normally somewhere in the region of 6% to 20% for most events, which indicates that there is absolutely zero money in the market for the bookies, which in itself is as good an indication as it gets that the league is done and dusted.
You are right that for the bookies to lose £1000, someone would have to bet 1000 x £1000, i.e.£1 million which puts it into perspective!