David Cameron has appointed to the post of equalities minister a second Conservative MP who voted against gay marriage.

Caroline Dinenage, the MP for Gosport, will join Nicky Morgan, the education secretary, in the Equalities Office. Morgan also voted against equal marriage, but later indicated she had changed her mind.

Pink News reported in 2013 that Dinenage had said in a letter to a constituent that the “state has no right” to redefine the meaning of marriage and that “preventing same-sex couples from being allowed to marry takes nothing away from their relationship”.

She later told the Portsmouth News: “I can see some of the points in it but it’s more the actual way the bill is written. I think it’s written in a hurried and ill-thought-out way and we haven’t really looked at what the potential long-term consequences are, particularly given that there is a quadruple lock on the Church of England but there isn’t that sort of protection for other faiths.

“I’m concerned that in the future, teachers may be forced to teach civil partnership and gay marriage whether it’s in their religious belief to do so or not. It seems that in some ways we’re marginalising some people’s religious freedom in favour of sexual freedom.”

Cameron caused controversy when he originally gave the equalities brief to Morgan in the previous government, as she had also voted against same-sex marriage.

Morgan has since said she would probably vote in favour if she could do so again.