Depends on the amount of loot, £0-2000, apologize and nothing happens. £2000-10,000 prosecution for recovery of paid benefits. £10,000-20,000 seizure of assets (if you legally own any) to pay and community service. £20,000 + is those said plus prison (up to a year). Small frauds and every 18 months or so seems the smoothest way
The EDD will have you repay all the benefits you have collected plus interest and maybe in the future you will be denied or under scrutinize
That would be fraud its a felony and about five years in jail and big fines