In short, a related bet is when one selection impacts the rest of the bet. You might also see this referred to as a related contingency. If you're trying to place a multiple bet and the website is refusing the bet or saying that there are insufficient selections for the bet, this is likely the reason!
Take, for example, a double bet for Manchester United to win 3-1 and Manchester United to win in 90-minutes. If Manchester United win 3-1, this of course means that they'll also win the match outright. The price for them to win 3-1 already takes this into account, so both selections cannot be combined into one bet.
Please note we won't accept a related bet under any circumstances and related bets accepted in error will be settled as split stake singles.