The numbers of civil partnership registrations in England and Wales has plunged below 1000 for the first time – as couples opt to marry instead.

Civil partnerships were introduced as under Tony Blair’s premiership in 2004 to allow gay unions ‘separate’ from marriage.

Following the introduction of same-sex marriage in England and Wales in 2014, the government opted to preserve civil partnerships as an option for same-sex couples, rather than close them off to new couples or abolish them.

But data from the Office of National Statistics this week shows that the number of couples who have opted to enter a civil partnership has plunged since equal marriage became law.

Just 861 couples entered civil partnerships in 2015, a drop of 80 percent from 2012, prior to same-sex marriage legislation being filed, when 6,362 did so.

It also represents a halving of new partnerships since 2014, when 1,683 couples entered unions.

Two-thirds (66%) of civil partnerships formed in 2015 were between men – the highest proportion since civil partnership formations were introduced in 2005.

However, they remain popular with some groups, including older gay couples.

Nearly half (48%) of all civil partners forming a partnership in 2015 were aged 50 and over; compared with 19% in 2013 prior to equal marriage.

Proponents of civil partnerships say they remain a lifeline for people who may not feel comfortable entering a marriage for religious or personal reasons, but still want partnership rights.

Elizabeth McLaren of the ONS said: “Civil partnerships have fallen sharply since the introduction of marriages for same sex couples in March 2014.

“On the other hand, civil partnership dissolutions have increased due to the rising number of civil partnerships that were formed since they were introduced in December 2005.

“Dissolutions are likely to reduce in the future as more same-sex couples form marriages instead of civil partnerships.”

A government consultation previously found that the option should be kept open for the time being.