It only takes one look at Boris Johnson to know he’s a man of impeccable style—but the British prime minister’s taste for the finer things in life might have landed him in some pretty murky water. Britain’s political spending watchdog announced Wednesday that it’s launching a formal investigation into how he funded lavish renovations at his Downing Street home. The decorations are reported to have cost around £200,000 ($280,000), which is way above the PM’s annual £30,000 allowance for improvements. He reportedly blamed the out-of-control spending on his fiancée, Carrie Symonds, with the Daily Mail reporting that he was heard raging: “The cost is totally out of control—she’s buying gold wallpaper!” Johnson’s office said he met the costs out of his own pocket, but the U.K. Electoral Commission said Wednesday that there a “reasonable grounds to suspect that an offense or offenses may have occurred.” It added that it has begun a “formal investigation” to “establish whether this is the case.”