The longterm gay partner of a Missouri trooper is suing to access survivor benefits.

Dennis Engelhard, 49, was a state trooper killed in the line of duty while responding to an accident on Christmas Day of last year.

Usually, the partners of Missouri State Highway Patrol employees are entitled to an annuity of 50 per cent of the employee’s average salary if the employee is killed on duty.

But because Mr Englelhard’s partner Kelly Glossip is male and the pair could not marry, or have any marriage recognised by the state, he will receive nothing.

Mr Glossip said: “Dennis and I loved each other and lived in a committed relationship for 15 years. We depended on each other emotionally and financially in our life together like any other committed couple. We exchanged rings and would have married in Missouri if the state didn’t exclude us from marriage.

“I‘m just seeking the same financial protections the state provides to heterosexual couples. It is hard enough coping with the grief of losing Dennis. It is even more painful to have the state treat Dennis and me as though we were total strangers.”

Mr Engelhard was investigating an accident on Interstate 44 in Eureka last Christmas Day when he was killed by a car.

Following his death, all US. and Missouri flags were flown at half-staff and Mr Glossip was recognised as his surviving partner at a Washington DC ceremony in May to commemorate police officers killed in the line of duty.

Mr Glossip will now sue to win the benefits given to heterosexual spouses and the American Civil Liberties Union (ACLU) filed a lawsuit on his behalf this week.

Anthony Rothert, legal director of the ACLU of Eastern Missouri, said: “Kelly is merely seeking the same treatment he would have received if his partner had been a woman, rather than a man.

“Kelly may not have been able to marry the person of his choice under Missouri state law, but he is still entitled to equal protection and the fundamental right to the family relationship he formed with Dennis Engelhard. He is seeking the same dignity and security for his family that is granted to other state troopers’ families.”