Well, this is a scam.
Try 13.7M to 1 odds on winning the lottery. That means you should get back £13.7M for your £1 stake.
In reality, it works out more like £4M on a good day or £1M on a bad day. Try £2M as an average payout.
But it is the only place you can put £1 on to win £1M+….and it’s fairly unfixed.