It depends how important ten pounds is to you and your family. Small scale betting is not a sin, unless it interferes with our ability to meet our financial obligations, or we become addicted to gambling.
The Catechism of the Catholic Church:
2413 Games of chance (card games, etc.) or wagers are not in themselves contrary to justice. They become morally unacceptable when they deprive someone of what is necessary to provide for his needs and those of others. The passion for gambling risks becoming an enslavement. Unfair wagers and cheating at games constitute grave matter, unless the damage inflicted is so slight that the one who suffers it cannot reasonably consider it significant.