The US state of Pennsylvania is to pay at least $400 (£250) an hour to a private law firm who will defend a 1996 state law banning equal marriage in a legal challenge brought against it.

The Morning Call reported that law firm Lamb McErlane PC of West Chester, will take on the case meaning William H Lamb, a former state Supreme Court Justice, will be personally paid $400 per hour out of taxpayer money. His associates will also earn $325 (£200) an hour. State lawyers will also be paid for working on the case.

The 1996 state law specifically defines marriage as between one man and one woman. It also specifies that same-sex marriages entered into out of state will not be recognised in Pennsylvania.

The American Civil Liberties Union (ACLU) in Pennsylvania which brought the challenge, argues that the measure is unconstitutional, and that it violates “the equal protection and due process clauses that protect against discrimination and infringement on liberties.”

The state attorney general Kathleen Kane has said she will not defend the state’s ban on equal marriage, following the lawsuit being filed to challenge the ban. This left the defense up to Pennsylvania Governor Tom Corbett.

Corbett’s administration is also currently in the throws of a separate legal battle to stop a county clerk from issuing marriage licences to same-sex couples.

ThinkProgess reports that last year, House Speaker John Boehner spent $2.3 million ( £1.47 million) of taxpayer money in an unsuccessful attempt to defend the federal Defense of Marriage Act, which was deemed unconstitutional back in June.