(that's a) likely story
A phrase used to express disbelief of an excuse or explanation. He said he had to stay late at the office again. That's a likely story—he's probably out with his friends! The cat ate your science project? Likely story.
a likely story
used to express disbelief of an account or excuse.a ˈlikely story
(spoken, ironic) used for showing that you do not believe what somebody has said: They said they’d found the wallet on the ground outside the pub — a likely story!