JEFFERSON CITY -- Missouri Attorney General Jay Nixon clearly isn't done smacking around a local utility giant over its smaller-than-requested rate increase.

Nixon announced Monday that he had filed an appeal in the Cole County Circuit Court against a May decision by the state's utility regulator to grant AmerenUE a $43 million increase. Ameren had asked for $361 million.

The Missouri Public Service Commission (PSC) has already denied Nixon one re-hearing of the AmerenUE rate rise. But the attorney general, expected to be the Democrats' sole gubernatorial contender in 2008, isn't letting the unpopular electicity provider off the hook.

"Ameren is not entitled to any rate increase, and instead should have received a rate cut from the PSC, as my office had requested," Nixon stated in Monday's release.

The PSC late last month denied applications from both Ameren and its opponents, including Nixon, to rehear its rate decision. Nixon had filed a motion with the PSC a month earlier for a re-hearing, hoping to turn the rise into a reduction.

The release claimed that Nixon's office "conducted an extensive audit" of Ameren's books following the utility's initial $361 million request. That uncovered instances of "omissions," "improper accounting proposals" and "overstated costs" in the request, the release stated.

Hence the AG's decision to take Ameren to the courts after its PSC rejection. "We are appealing the PSC decision to the circuit court to stand up for Missouri's families," Nixon stated.

AmerenUE, Missouri's largest electricity supplier, operates nine power plants providing around 1.2 million electricity customers in eastern Missouri, including St. Louis. The utility also supplies 110,000 customers with natural gas.