From Corals rules,also applies to the internet.Note it works both ways.
2.19 A betting shop is, by its very nature, a fast moving environment. Odds move rapidly and bets are taken continuously, consequently mistakes can occur. We will do all that we can to avoid this but we cannot accept responsibility for any obvious errors or omissions in respect of the announcing, publishing or marking of prices, handicaps, place terms, runners or results despite our every effort to ensure total accuracy. If we do make an obvious error then the following rules will apply:
We reserve the right to correct any obvious error made on a bet placed in one of our “betting in running” markets and settle at the correct price or terms which were actually available with Coral (absent the obvious error) at the time the bet was struck;
When a bet is placed on a market offered before an event has started and more advantageous odds than those actually available with Coral are applied, we will either settle the bet at the correct price or terms available with Coral or, on condition that you can provide us with verification, at the best price or on the best terms available with any of the following companies at the time the bet was struck: - Bet 365, Betfred, Ladbrokes, Stan James, Totesport, William Hill.
Where the incorrect odds or terms are less advantageous than those available with Coral the odds or terms will be amended to the correct odds or terms available.
For example:
Where Coral’s actual price for Ronaldo to score the first goal is 6/1 but you are quoted 66/1 in error then you will be able to determine whether your bet should be settled at 6/1 or the best price available with the companies listed above even if this price is higher than the actual Coral price.
Where, however, you have been quoted 6/4 on the same bet the price will be amended upwards to 6/1.